Merge pull request #123 from DeterminateSystems/update-flake-checker-action

Update flake checker action to v4

Author: lucperkins

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: DeterminateSystems/flake-checker-action@v3
+    - uses: DeterminateSystems/flake-checker-action@v4
       with:
         fail-mode: true