chore: also create a branch based on the tag to avoid dangling commits (

#1098)

<!-- markdownlint-disable MD041 -->
#### What this PR does / why we need it

currently our tagged releases do not have branch accomodating them,
leading to dangling commits. (see
https://github.com/open-component-model/ocm/tree/v0.18.0-rc.1 for an
example)

This fixes this by also creating an appropriate release branch.

This might introduce issues with things like the release drafter though,
so this is likely only the first line of commits for this.

#### Which issue(s) this PR fixes
<!--
Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
-->
fix #1099

.github/workflows/release-drafter.yaml

@@ -3,7 +3,10 @@ name: Release Drafter
 on:
   push:
     branches:
-      - releases/*
+      # we only want to draft release notes for the base version,
+      # e.g. for releases/v0.18, we draft v0.18.0 for all RCs
+      # this means that we explicitly don't want to draft release notes for releases/v0.18.0 or releases/v0.18.1
+      - 'releases/v[0-9]+.[0-9]+'
 
 permissions:
   contents: read

.github/workflows/release.yaml

@@ -160,7 +160,8 @@ jobs:
         git commit -m "Release $RELEASE_VERSION"
         msg="Release ${{ env.RELEASE_VERSION }}"
         git tag --annotate --message "${msg}" ${{ env.RELEASE_VERSION }}
-        git push origin ${{ env.RELEASE_VERSION }}
+        # push both the tag as well as a release branch with that tag.
+        git push origin releases/${{ env.RELEASE_VERSION }} ${{ env.RELEASE_VERSION }}
 
     - name: Create GPG Token file from Secret
       run: |