Fix version comment for stale action

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

.github/workflows/stale.yml

@@ -14,7 +14,7 @@ jobs:
       issues: write
       pull-requests: write
     steps:
-      - uses: actions/stale@6f05e4244c9a0b2ed3401882b05d701dd0a7289b # v6
+      - uses: actions/stale@6f05e4244c9a0b2ed3401882b05d701dd0a7289b # v7.0.0
         with:
           days-before-stale: 28
           days-before-close: 14