chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/mirror.yml

@@ -11,7 +11,7 @@ jobs:
   mirror-repo:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
         with:
           fetch-depth: 0
       - uses: yesolutions/mirror-action@master