fix stale bot (#191)

Author: tac0turtle

.github/workflows/stale.yml

@@ -13,6 +13,8 @@ jobs:
           stale-pr-message: "This pull request has been automatically marked as stale because it has not had
     recent activity. It will be closed if no further activity occurs. Thank you
     for your contributions."
-          days-before-stale: 10
-          days-before-close: 4
-          exempt-pr-labels: "S:wip"
+          days-before-stale: -1
+          days-before-close: -1
+          days-before-pr-stale: 20
+          days-before-pr-close: 10
+          exempt-pr-labels: "pinned, security, proposal, blocked"