chore(deps): update dessant/lock-threads action to v6 (#14389)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/lock-closed-issues.yml

@@ -12,7 +12,7 @@ jobs:
     if: github.repository == 'vuejs/core'
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@v5
+      - uses: dessant/lock-threads@v6
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           issue-inactive-days: '14'