Update remaining GitHub Actions refs for Node 24

Author: MaxGhenis

.github/workflows/changelog_entry.yaml

@@ -9,7 +9,7 @@ jobs:
     name: Check changelog fragment
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Check for changelog fragment
         run: |
           FRAGMENTS=$(find changelog.d -type f ! -name '.gitkeep' | wc -l)