Wheel builder: set shell to bash when getting current commit

Author: howetuft

.github/workflows/wheel-builder.yml

@@ -92,6 +92,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Get current commit
+        shell: bash
         id: current-commit
         run: |
           echo "commit=$(git rev-parse HEAD)" >> $GITHUB_OUTPUT