Fix branch name

Author: KLMatlock

.github/workflows/dependabot-push.yml

@@ -79,9 +79,9 @@ jobs:
         if: steps.generate_fragment.outputs.fragment_created == 'true'
         run: |
           FRAGMENT_DIR="changes"
-          branch_name="${{ github.head_ref }}"
+          branch_name="${GITHUB_HEAD_REF:-${GITHUB_REF#refs/heads/}}"
           sanitized_name=$(echo "$branch_name" | sed 's|/|_|g')
-          fragment_name="${sanitized_name}.misc"
+          fragment_name="${sanitized_name}.misc.rst"
           fragment_path="${FRAGMENT_DIR}/${fragment_name}"
 
           echo "Adding fragment: ${fragment_path}"