⬆️ Updates dessant/lock-threads action to v6

Author: renovate[bot]

.github/workflows/lock.yml

@@ -9,7 +9,7 @@ jobs:
   lock:
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@v2.0.3
+      - uses: dessant/lock-threads@v6
         with:
           github-token: ${{ github.token }}
           issue-lock-inactive-days: '180'