*: add client support for discovery-srv-name

[hexfusion]

Fixes #10238

[codecov-io]

Codecov Report

Merging #10250 into master will increase coverage by 0.05%.
The diff coverage is 77.77%.

@@            Coverage Diff             @@
##           master   #10250      +/-   ##
==========================================
+ Coverage   71.75%   71.81%   +0.05%     
==========================================
  Files         390      390              
  Lines       36351    36369      +18     
==========================================
+ Hits        26083    26117      +34     
+ Misses       8464     8443      -21     
- Partials     1804     1809       +5

Impacted Files	Coverage Δ
client/discover.go	0% <0%> (ø)	⬆️
etcdctl/ctlv3/ctl.go	100% <100%> (ø)	⬆️
pkg/srv/srv.go	80.88% <100%> (+1.85%)	⬆️
etcdmain/grpc_proxy.go	64.58% <100%> (+0.14%)	⬆️
etcdmain/gateway.go	33.87% <50%> (+1.08%)	⬆️
etcdmain/util.go	5.17% <50%> (ø)	⬆️
etcdctl/ctlv3/command/global.go	59% <66.66%> (+0.21%)	⬆️
etcdctl/ctlv2/command/util.go	45.5% <87.5%> (+0.93%)	⬆️
proxy/grpcproxy/watcher.go	89.79% <0%> (-4.09%)	⬇️
pkg/transport/listener.go	58.67% <0%> (-4.09%)	⬇️
... and 25 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 83304cf...e0f7807. Read the comment docs.

[gyuho]

@hexfusion Can we add tests? Runbook should be good enough (e.g. https://github.com/etcd-io/etcd/tree/master/tests/docker-dns-srv).

[hexfusion]

@gyuho I added tests for docker-dns-srv-test-certs-run, let me know if this is what you were thinking, thanks.

[gyuho]

@hexfusion Also changelogs? Then should be good to merge. Thanks!

[hexfusion]

@gyuho changelog updated.

[gyuho]

lgtm thanks!

[hexfusion]

/cc @mrrandrade