Initial codecov integration

[taylanisikdemir]

What changed?
Adding codecov github action to report coverage numbers. We will iterate on the configuration. For not it's supposed to be informational only and not blocking PRs.

Why?
We have coveralls integration but exploring codecov which is recommended by other Go OS teams in the org. Ideally we get accurate reporting and enforcements with this integration.

How did you test it?
PR checks trigger the github action that runs codecov. It's supposed to comment on the PR.

[coveralls]

Pull Request Test Coverage Report for Build 018e0fd6-4168-4905-9ce1-9efc2bbf8aba

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 112 unchanged lines in 18 files lost coverage.
• Overall coverage decreased (-0.04%) to 63.1%

---

Files with Coverage Reduction	New Missed Lines	%
common/peerprovider/ringpopprovider/config.go	2	81.58%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/history/execution/mutable_state_util.go	2	37.63%
service/matching/db.go	2	73.23%
service/matching/taskListManager.go	2	80.46%
common/log/tag/tags.go	3	50.18%
common/persistence/statsComputer.go	3	94.29%
common/task/fifo_task_scheduler.go	3	84.54%
service/history/queue/timer_gate.go	3	95.83%
common/persistence/nosql/nosqlplugin/cassandra/tasks.go	4	76.09%

Totals
Change from base Build 018e0fc4-a6e5-42bf-8663-3ae9df10ab32:	-0.04%
Covered Lines:	92550
Relevant Lines:	146671

---

💛 - Coveralls

[codecov]

Welcome to Codecov 🎉

Once merged to your default branch, Codecov will compare your coverage reports and display the results in this comment.

Thanks for integrating Codecov - We've got you covered ☂️