Increase limit of stale action operations (pipe-cd#4671)

Signed-off-by: 鈴木 優耀 <[email protected]>

.github/workflows/stale.yaml

@@ -9,6 +9,7 @@ jobs:
     steps:
       - uses: actions/stale@v8
         with:
+          operations-per-run: 1000
           # Issues
           stale-issue-message: 'This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 7 days.'
           close-issue-message: 'This issue was closed because it has been stalled for 7 days with no activity. Feel free to reopen if still applicable.'