get branch-name from github var

[friedrichwilken]

Description

There was a bug in the workflow that would pass the wrong branch name:
for the branch release-1.0 the input "release-${VERSION}" would generate the name release-1.0.x because the VERSION always has three numbers instead of the two of the branch name. So, this PR changes this use ${{ GITHUB_REF_NAME }} to get the var.

e.g. we are on branch release-1.0; the generated version would be release-1.0.1.
"release-${VERSION}" would lead to the branch name release-1.0.1 instead of release-1.0.

Docs for GITHUB_REF_NAME:

The short ref name of the branch or tag that triggered the workflow run. This value matches the branch or tag name shown on GitHub. For example, feature-branch-1. For pull requests, the format is <pr_number>/merge.

Related issue(s)
issue