feat: add stale yml (#109)

.github/.stale.yml

@@ -0,0 +1,41 @@
+# Configuration for probot-stale - https://github.com/probot/stale
+
+# Label applied when closing
+staleLabel: stale
+
+# Configuration settings that are specific to just 'issues' or 'pulls':
+pulls:
+  daysUntilStale: 60
+  daysUntilClose: 28
+  limitPerRun: 5
+  markComment: >
+    This pull request has been marked as stale due to 60 days of inactivity.
+    It will be closed in 4 weeks if no further activity occurs. If you think
+    that's incorrect or this pull request should instead be reviewed, please simply
+    write any comment. Even if closed, you can still revive the PR at any time.
+    Thank you for your contributions.
+  unmarkComment: >
+    This pull request/issue is no longer marked as stale.
+  closeComment: >
+    This pull request/issue has been closed due to lack of activity. If you think that
+    is incorrect, or the pull request requires review, you can revive the PR at any time.
+issues:
+  daysUntilStale: 350
+  daysUntilClose: 14
+  markComment: >
+    This issue has been marked as stale due to 350 days of inactivity.
+    It will be closed in 2 weeks if no further activity occurs. If this issue is still
+    relevant, please simply write any comment. Even if closed, you can still revive the
+    issue at any time or discuss it on the dev@apisix.apache.org list.
+    Thank you for your contributions.
+  unmarkComment: >
+    This issue is no longer marked as stale.
+  closeComment: >
+    This issue has been closed due to lack of activity. If you think that
+    is incorrect, or the issue requires additional review, you can revive the issue at
+    any time.
+  # Issues with these labels will never be considered stale.
+  exemptLabels:
+    - bug
+    - enhancement
+    - good first issue