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

Author: renovate[bot]

.github/workflows/release-pr.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           # This makes Actions fetch all Git history so that Changesets can generate changelogs with the correct commits
           fetch-depth: 0