Update workflow to use environment variables

- The workflow has been updated to use environment variables instead of hardcoded values.
- This change improves the flexibility and maintainability of the workflow.
- The changes include using `$GITHUB_OUTPUT` to store the commit message and `$COMMIT_MESSAGE` to retrieve it.

.gitea/workflows/main.yml

@@ -38,8 +38,6 @@ jobs:
     - name: Setting commit message
       id: commit-message
       run: COMMIT_MESSAGE=$(git log -1 --pretty=%B); echo "COMMIT_MESSAGE=$COMMIT_MESSAGE" >> "$GITHUB_OUTPUT" && echo "commit message is '$COMMIT_MESSAGE'"
-    - name: Retrieve commit message
-      run: echo "${{ steps.commit-message.outputs.COMMIT_MESSAGE }}"
 
     # Create a release for this specific version
     - name: Update Release with Files