Updates actions/checkout

Author: philnash

.github/workflows/tests.yml

@@ -49,7 +49,7 @@ jobs:
     env:
       RAILS_VERSION: ${{ matrix.rails }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up Ruby ${{ matrix.ruby }}
         uses: ruby/setup-ruby@v1
         with: