Whitelist announcement label from stalebot (#2747)

Chris Elion · web-flow · commit 5a2c364d11ea · 2019-10-17T10:35:27.000-07:00
diff --git a/.github/stale.yml b/.github/stale.yml
@@ -24,3 +24,4 @@ issues:
     - bug
     - request
     - help-wanted
+    - announcement
