*: upgrade etcd to v3.4.30 (#7884)

[ti-chi-bot]

This is an automated cherry-pick of #7884

What problem does this PR solve?

Issue Number: close #7904, ref #5520.

• Release note: https://github.com/etcd-io/etcd/releases/tag/v3.4.30
• Code changes are caused by etcd-io/etcd@6de105e.

What is changed and how does it work?

Upgrade etcd to v3.4.30 and adopt the latest code changes.

Check List

Tests

• Unit test
• Integration test

Release note

Upgrade etcd to v3.4.30 to adopt the security patch.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• HuSharp
• rleungx

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.80%. Comparing base (8e97f3b) to head (2328bee).
Report is 1 commits behind head on release-7.1.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-7.1    #7889      +/-   ##
===============================================
+ Coverage        74.74%   74.80%   +0.05%     
===============================================
  Files              411      412       +1     
  Lines            41732    41750      +18     
===============================================
+ Hits             31194    31230      +36     
+ Misses            7788     7779       -9     
+ Partials          2750     2741       -9     

Flag	Coverage Δ
unittests	74.80% <100.00%> (+0.05%)	⬆️

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[HuSharp]

Do we need to keep consistent with 1.59.0 in master?
https://github.com/tikv/pd/pull/7884/files#diff-33ef32bf6c23acb95f5902d7097b7a1d5128ca061167ec0716715b0b9eeaa5f6L58

[JmPotato]

No, let's keep it the same as the grpc version used by etcd: https://github.com/etcd-io/etcd/blob/ff2304879e1bf1cf6c7c5669bc08f8e32296582e/go.mod#L42.

[JmPotato]

/merge

[ti-chi-bot]

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/run-all-tests

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 2328bee