small fix for github workflow

related to #3

Author: tpokorra

.github/workflows/main.yml

@@ -32,7 +32,7 @@ jobs:
     - name: Run black --check .
       run: black --check .
     - name: If needed, commit black changes to the pull request
-        if: failure()
+        if: ${{ failure() }}
         run: |
           black .
           git config --global user.name 'autoblack'