update vendor of gogo/protobuf to v1.2.1

[lifupan]

Description of problem

I need to update runtime's vendor, but before I update runtime's vendor, agent needs
to update it first, otherwise, it will complains as below:

$ dep ensure
Solving failure: No versions of github.com/kata-containers/agent met constraints:
48dd1c0: Could not introduce github.com/kata-containers/agent@48dd1c031530fce9bf16b0f6a7305979cedd8fc9, as it has a dependency on github.com/gogo/protobuf with constraint 342cbe0a04158f6dcb03ca0079991a51a4248c02, which has no overlap with existing constraint ba06b47c162d49f2af050fb4c75bcbc86a159d5c from (root)
1.6.3: Could not introduce github.com/kata-containers/agent@1.6.3, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.6.2: Could not introduce github.com/kata-containers/agent@1.6.2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.6.1: Could not introduce github.com/kata-containers/agent@1.6.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.6.0: Could not introduce github.com/kata-containers/agent@1.6.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.5: Could not introduce github.com/kata-containers/agent@1.5.5, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.4: Could not introduce github.com/kata-containers/agent@1.5.4, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.3: Could not introduce github.com/kata-containers/agent@1.5.3, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.2: Could not introduce github.com/kata-containers/agent@1.5.2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.1: Could not introduce github.com/kata-containers/agent@1.5.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.0: Could not introduce github.com/kata-containers/agent@1.5.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.4.3: Could not introduce github.com/kata-containers/agent@1.4.3, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.4.2: Could not introduce github.com/kata-containers/agent@1.4.2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.4.1: Could not introduce github.com/kata-containers/agent@1.4.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.4.0: Could not introduce github.com/kata-containers/agent@1.4.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.3.1: Could not introduce github.com/kata-containers/agent@1.3.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.3.0: Could not introduce github.com/kata-containers/agent@1.3.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.2.2: Could not introduce github.com/kata-containers/agent@1.2.2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.2.1: Could not introduce github.com/kata-containers/agent@1.2.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.2.0: Could not introduce github.com/kata-containers/agent@1.2.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.1.1: Could not introduce github.com/kata-containers/agent@1.1.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.1.0: Could not introduce github.com/kata-containers/agent@1.1.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.0.0: Could not introduce github.com/kata-containers/agent@1.0.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
0.3.0: Could not introduce github.com/kata-containers/agent@0.3.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
0.2.0: Could not introduce github.com/kata-containers/agent@0.2.0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
0.0.1: Could not introduce github.com/kata-containers/agent@0.0.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.7.0-alpha1: Could not introduce github.com/kata-containers/agent@1.7.0-alpha1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.7.0-alpha0: Could not introduce github.com/kata-containers/agent@1.7.0-alpha0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.6.0-rc2: Could not introduce github.com/kata-containers/agent@1.6.0-rc2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.6.0-rc1: Could not introduce github.com/kata-containers/agent@1.6.0-rc1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.0-rc2: Could not introduce github.com/kata-containers/agent@1.5.0-rc2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.5.0-rc1: Could not introduce github.com/kata-containers/agent@1.5.0-rc1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.3.0-rc1: Could not introduce github.com/kata-containers/agent@1.3.0-rc1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
1.3.0-rc0: Could not introduce github.com/kata-containers/agent@1.3.0-rc0, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
master: Could not introduce github.com/kata-containers/agent@master, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.1: Could not introduce github.com/kata-containers/agent@stable-1.1, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.2: Could not introduce github.com/kata-containers/agent@stable-1.2, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.3: Could not introduce github.com/kata-containers/agent@stable-1.3, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.4: Could not introduce github.com/kata-containers/agent@stable-1.4, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.5: Could not introduce github.com/kata-containers/agent@stable-1.5, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.
stable-1.6: Could not introduce github.com/kata-containers/agent@stable-1.6, as it is not allowed by constraint 48dd1c0 from project github.com/kata-containers/runtime.

Expected result

(replace this text with an explanation of what you thought would happen)

Actual result

(replace this text with details of what actually happened)

---

(replace this text with the output of the kata-collect-data.sh script, after
you have reviewed its content to ensure it does not contain any private
information).