chore(workflow): use actions/checkout@v6

Author: tarnishablec

.github/workflows/changeset-release.yml

@@ -19,7 +19,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - name: Checkout Repo
-              uses: actions/checkout@v4
+              uses: actions/checkout@v6
               with:
                   # Critical: Fetch full history for accurate changelog generation
                   fetch-depth: 0