Enable stale and no-response bots

.github/no-response.yml

@@ -0,0 +1,8 @@
+# ProBot No Response (https://probot.github.io/apps/no-response/)
+
+daysUntilClose: 7
+responseRequiredLabel: 'need more info'
+closeComment: >
+  This issue has been automatically closed because there was no response to a
+  request for more information from the issue opener. Please leave a comment or
+  open a new issue if you have additional information related to this issue.

.github/stale.yml

@@ -0,0 +1,14 @@
+# ProBot Stale (https://probot.github.io/apps/stale/)
+
+daysUntilStale: 90
+daysUntilClose: 7
+exemptLabels:
+  - accepted
+  - bug
+  - enhancement
+  - meta
+staleLabel: stale
+markComment: >
+  This issue has been automatically marked as stale because it has not had
+  recent activity. It will be closed if no further activity occurs.
+closeComment: false