check if shell bash exits as expected

.github/workflows/ci.yaml

@@ -79,6 +79,7 @@ jobs:
       - run: cargo install cargo-insta
       - run: pip install black[d]==22.12.0
       - name: Run tests
+        shell: bash
         run: |
           cargo insta test --all --delete-unreferenced-snapshots
           git diff --exit-code