fix(release): set the correct release branch

fix(release): set the correct release branch

The default branch here is master not main. I missed this in the onboarding in !137 (merged)

This should fix failures like https://gitlab.com/gitlab-org/ruby/gems/labkit-ruby/-/jobs/10133227989

fix(release): don't manually update the changelog

The semantic-release job from common-ci-tasks should take care of this already. No need to do it manually.