CI: set bash as default shell for update-formulas workflow

Author: maxim-belkin

.github/workflows/update-formulas.yml

@@ -23,6 +23,9 @@ jobs:
     runs-on: ubuntu-22.04
     container:
       image: ghcr.io/homebrew/ubuntu22.04:master
+    defaults:
+      run:
+        shell: bash
     env:
       HOMEBREW_GITHUB_API_TOKEN: ${{ secrets.BUMP_GITHUB_TOKEN }}
       GITHUB_TOKEN: ${{ secrets.BUMP_GITHUB_TOKEN }}