ci: add pushing of test empty commit before release

Author: MingweiSamuel

.github/workflows/release.yml

@@ -60,6 +60,11 @@ jobs:
           fetch-depth: 0
           token: ${{ steps.generate_token.outputs.token }}
 
+      - name: Push test commit
+        run: |
+          git commit -m 'pre-release test commit' --allow-empty
+          git push
+
       - name: Install nightly toolchain
         uses: actions-rs/toolchain@v1
         with: