Use releasebot token for prepare-release PR creation to trigger workflows (#465)

Author: lbarcziova

.github/workflows/prepare-release.yml

@@ -34,3 +34,4 @@ jobs:
           title: Release ${{ inputs.version }}
           body: Update the changelog and the specfile for release ${{ inputs.version }}.
           delete-branch: true
+          token: ${{ secrets.RELEASEBOT_GITHUB_TOKEN }}