chore: change mailbox of issues and pull requests from dev to notifications

--- a/.asf.yaml
+++ b/.asf.yaml
@@ -37,6 +37,6 @@ github:
        required_approving_review_count: 1
 notifications:
  commits: notifications@seata.apache.org
  issues: dev@seata.apache.org
  pullrequests: dev@seata.apache.org
  issues: notifications@seata.apache.org
  pullrequests: notifications@seata.apache.org
  discussions: dev@seata.apache.org