chore(deps): update dependency protobuf to v3.12.1

[renovate-bot]

This PR contains the following updates:

Package	Update	Change
protobuf	minor	==3.11.3 -> ==3.12.1

---

Renovate configuration

📅 Schedule: At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻️ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR has been generated by WhiteSource Renovate. View repository job log here.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@117d110). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             master      #419   +/-   ##
==========================================
  Coverage          ?   100.00%           
==========================================
  Files             ?        26           
  Lines             ?      1451           
  Branches          ?       300           
==========================================
  Hits              ?      1451           
  Misses            ?         0           
  Partials          ?         0           

Impacted Files	Coverage Δ
gapic/utils/rst.py	100.00% <0.00%> (ø)
gapic/generator/options.py	100.00% <0.00%> (ø)
gapic/utils/doc.py	100.00% <0.00%> (ø)
gapic/samplegen_utils/types.py	100.00% <0.00%> (ø)
gapic/samplegen_utils/utils.py	100.00% <0.00%> (ø)
gapic/utils/__init__.py	100.00% <0.00%> (ø)
gapic/schema/api.py	100.00% <0.00%> (ø)
gapic/utils/filename.py	100.00% <0.00%> (ø)
gapic/schema/wrappers.py	100.00% <0.00%> (ø)
gapic/samplegen_utils/__init__.py	100.00% <0.00%> (ø)
... and 16 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 117d110...e46c879. Read the comment docs.