Update actions/checkout action to v4 (#959)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/pr.yml

@@ -32,7 +32,7 @@ jobs:
 
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install Node.js from .nvmrc
         uses: actions/setup-node@v4

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           # Fetch all history (required for publishing which looks at history)
           fetch-depth: 0