Missing shell

Author: stevebux

.github/actions/acceptance-tests/action.yml

@@ -50,6 +50,7 @@ runs:
       env:
         GITHUB_TOKEN: ${{ env.GITHUB_TOKEN }}
         PR_NUMBER: ${{ steps.pr_exists.outputs.pr_number }}
+      shell: bash
       run: |
         if [[ -z "$PR_NUMBER" ]]; then
           echo "No pull request detected; proxy deployment was deployed."