updated stale Bot rules

Author: SaicharanKandukuri

.github/stale.yml

@@ -4,8 +4,8 @@ daysUntilClose: 7
 # Issues with these labels will never be considered stale
 exemptLabels:
   - pinned
-  - security
   - enhancement
+  - Todo
 # Label to use when marking an issue as stale
 staleLabel: stale
 # Comment to post when marking an issue as stale. Set to `false` to disable