[FLINK-17512] Add notification settings to .asf.yaml

Author: zentol

.asf.yaml

@@ -3,3 +3,8 @@ github:
     squash: true
     merge: false
     rebase: true
+notifications:
+  commits:      [email protected]
+  issues:       [email protected]
+  pullrequests: [email protected]
+  jira_options: link label