Replace the tag name to latest if branch name is master

Created by: LinuxSuRen

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Use latest as tag name when the branch name is master.

Which issue(s) this PR fixes:

None.

Special notes for reviewers:

See the test result:

➜  console git:(master-to-latest) git cm
Switched to branch 'master'
Your branch is up to date with 'upstream/master'.
➜  console git:(master) git rev-parse --abbrev-ref HEAD | sed -e 's/\//-/g' | sed 's/master/latest/g'
latest

Does this PR introduced a user-facing change?

None

Additional documentation, usage docs, etc.:

None.