Update stale.yml with current labels and mark stale items as "stale" (microsoft#4831)

Author: natke

.github/stale.yml

@@ -6,12 +6,12 @@ daysUntilClose: 7
 
 # Issues with these labels will never be considered stale
 exemptLabels:
-  - "contributions are welcome"
-  - documentation
-  - enhancement
+  - status:contributions-welcome 
+  - status:more-info-needed 
+  - status:duplicate 
 
 # Label to use when marking an issue as stale
-staleLabel: wontfix
+staleLabel: stale
 
 # Comment to post when marking an issue as stale. Set to `false` to disable
 markComment: >