Update checkout action for Node 24

Author: wolski

.github/workflows/pkgdown.yaml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.3
 
       - name: Set up R
         uses: r-lib/actions/setup-r@v2

.github/workflows/r.yaml

@@ -14,7 +14,7 @@ jobs:
         r-version: ['4.5.2']
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.3
 
       - name: Set up R ${{ matrix.r-version }}
         uses: r-lib/actions/setup-r@v2