Fixed stale bot comment (#2072)

Signed-off-by: Marco Pracucci <marco@pracucci.com>

Author: pracucci

.github/stale.yml

@@ -20,7 +20,7 @@ staleLabel: stale
 # to disable.
 markComment: >
   This issue has been automatically marked as stale because it has not had any
-  activity in the past 30 days. It will be closed in 7 days if no further
+  activity in the past 60 days. It will be closed in 15 days if no further
   activity occurs. Thank you for your contributions.
 
 # Comment to post when closing a stale issue. Leave as