api: update leader when peer url updates

[rleungx]

What problem does this PR solve?

Close #3317

What is changed and how it works?

When returning the result of member, use the latest information from etcd

Check List

Tests

• Unit test

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tidb-ansible:
• Need to cherry-pick to the release branch

Release note

[codecov]

Codecov Report

Merging #3319 (20a6923) into master (ee0045a) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3319      +/-   ##
==========================================
+ Coverage   74.64%   74.72%   +0.08%     
==========================================
  Files         243      243              
  Lines       23136    23140       +4     
==========================================
+ Hits        17270    17292      +22     
+ Misses       4288     4269      -19     
- Partials     1578     1579       +1     

Flag	Coverage Δ
unittests	74.72% <100.00%> (+0.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/grpc_service.go	56.17% <100.00%> (+1.49%)	⬆️
server/schedule/region_scatterer.go	80.61% <0.00%> (-3.58%)	⬇️
server/tso/local_allocator.go	78.78% <0.00%> (-3.04%)	⬇️
server/handler.go	42.75% <0.00%> (-0.50%)	⬇️
client/client.go	64.93% <0.00%> (-0.38%)	⬇️
server/tso/allocator_manager.go	75.45% <0.00%> (+0.40%)	⬆️
server/config/persist_options.go	92.12% <0.00%> (+0.78%)	⬆️
pkg/btree/btree.go	86.26% <0.00%> (+0.96%)	⬆️
server/server.go	73.73% <0.00%> (+1.26%)	⬆️
... and 4 more

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[Yisaer]

LGTM

[Yisaer]

/merge

[ti-chi-bot]

@Yisaer: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/ti-community-prow repository.

[ti-chi-bot]

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

Commit hash: b0e8c0c

[ti-chi-bot]

@rleungx: Your PR has out-of-dated, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/ti-community-prow repository.