Add Github Stale to PyScript repo (#791)

* Add stale to pyscript repo

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Add tags: backlog, needs-triage, needs-work

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.github/stale.yaml

@@ -0,0 +1,25 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 60
+
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 7
+
+# Issues with these labels will never be considered stale
+exemptLabels:
+-   backlog
+-   needs-triage
+-   needs-work
+
+# Label to use when marking an issue as stale
+staleLabel: stale
+
+# Comment to post when marking an issue as stale. Set to `false` to disable
+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. Thank you
+    for your contributions.
+
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: >
+    This issue has been automatically closed because it has not had
+    recent activity. Thank you for your contributions.