Merge pull request #1173 from stephan-cr/upgrade-actions-checkout

Upgrade actions/checkout to v4

Author: raxod502

.github/workflows/ci.yml

@@ -13,7 +13,7 @@ jobs:
         emacs_version: [25, 26, 27, 28]
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: CI
         env:
           VERSION: ${{ matrix.emacs_version }}