Bump actions version

The current version was giving warnings in our workflow. I don't believe there's any serious issue with just bumping the version here.

Author: driesvints

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Test
         id: test
         uses: ./