Prevent bot to stale already acknowledged issues/FR

At the moment the gitactions-bot tries to set the `stale` label even on issues/feature requests already marked as acknowledged or even on milestones (see robinostlund#627 for example).

This modification should tell the bot to avoid those types of issues.

.github/workflows/close_inactive_issues.yml

@@ -16,8 +16,10 @@ jobs:
           days-before-issue-stale: 30
           days-before-issue-close: 14
           stale-issue-label: "stale"
+          exempt-all-milestones: true
+          exempt-issue-labels: 'acknowledged'
           stale-issue-message: "This issue is stale because it has been open for 30 days with no activity."
           close-issue-message: "This issue was closed because it has been inactive for 14 days since being marked as stale."
           days-before-pr-stale: -1
           days-before-pr-close: -1
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          repo-token: ${{ secrets.GITHUB_TOKEN }}