Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/conformance.yml

@@ -9,7 +9,7 @@ jobs:
   conformance:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: actions/setup-node@v4
         with:
           node-version: "24"