Ensure black formatting stability in workflow (#43)

* ensure black formatting stability

use psf/black@latest and set stability version to avoid workflow breaking

as per https://black.readthedocs.io/en/stable/integrations/github_actions.html#usage

* pin black action version

* upgrade black action

.github/workflows/black.yml

@@ -7,4 +7,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3.0.2
-      - uses: psf/black@22.8.0
+      - uses: psf/black@24.3.0
+        with:
+          version: "~= 22.0"