Replace ugorji/codec with json-iterator/go

[dims]

Kubernetes removed the usage for ugorji in the following PR:
Use json-iterator instead of ugorji for JSON. #48287

However since etcd still uses this library, we end up increasing the size of the binaries in kubernetes by a lot. See:
kubernetes/kubernetes#76506

Can we please switch over to json-iterator/go as well to eliminate the unnecessary code/size?

Change-Id: Ia8b267e9ada49b22a1cd3bd7c05450e32582dc91

Please read https://github.com/etcd-io/etcd/blob/master/CONTRIBUTING.md#contribution-flow.

[dims]

@gyuho @spzala any idea how i can get the amd64-e2e of the semaphoreci to pass?

[spzala]

@dims I don't see any failure related to your changes looking at quickly. Lately, CI is flakey. I will be reviewing the changes too. Thanks!

[liggitt]

github.com/ugorji/go is still listed in go.sum and is vendored... did you run go mod tidy && go mod vendor?

[dims]

@liggitt unfortunately the scripts/updatedep.sh does not seem to work well, it just nukes everything in go.mod and go.sum. So i am hesitating to add a commit with the cleanup

[codecov-io]

Codecov Report

Merging #10667 into master will decrease coverage by 0.11%.
The diff coverage is 40%.

@@            Coverage Diff             @@
##           master   #10667      +/-   ##
==========================================
- Coverage   71.63%   71.51%   -0.12%     
==========================================
  Files         393      394       +1     
  Lines       36629    36658      +29     
==========================================
- Hits        26238    26217      -21     
- Misses       8551     8590      +39     
- Partials     1840     1851      +11

Impacted Files	Coverage Δ
client/keys.go	91.45% <100%> (ø)	⬆️
client/json.go	37.93% <37.93%> (ø)
pkg/tlsutil/tlsutil.go	86.2% <0%> (-6.9%)	⬇️
pkg/fileutil/purge.go	65.9% <0%> (-6.82%)	⬇️
pkg/netutil/netutil.go	63.11% <0%> (-6.56%)	⬇️
etcdserver/api/v3rpc/lease.go	71.59% <0%> (-5.69%)	⬇️
pkg/logutil/zap_grpc.go	47.61% <0%> (-4.77%)	⬇️
proxy/grpcproxy/watcher.go	89.79% <0%> (-4.09%)	⬇️
pkg/testutil/recorder.go	77.77% <0%> (-3.71%)	⬇️
clientv3/leasing/txn.go	88.09% <0%> (-3.18%)	⬇️
... and 18 more

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[dims]

@liggitt cleaned up as well! dropped 45k+ LOC

[gyuho]

@dims Could you update the commit title to Expected commit title format '<package>{", "<package>}: <description>'?

[dims]

@gyuho ack will fix the commit message shortly

[dims]

@gyuho @spzala would you consider a backport to release-3.3 branch? (looks like k/k is using v3.3.10+ currently)

[gyuho]

@dims Sure, if it doesn't break compatibility. Would anything change in json-iterator/go?

[spzala]

@dims aha..all green checks, looks good :-)

[dims]

@gyuho exact same code in this PR applies cleanly to 3.3-release (except for the vanity url). So we should be good