added stale probot

Signed-off-by: Anton Kosiakov <anton.kosyakov@typefox.io>

.github/stale.yml

@@ -0,0 +1,19 @@
+# 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:
+  - pinned
+  - security
+# 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 removing the stale label. Set to `false` to disable
+unmarkComment: false
+# Comment to post when closing a stale Issue or Pull Request. Set to `false` to disable
+closeComment: false

.npmignore

@@ -5,4 +5,5 @@ node_modules
 .gitignore
 .npmignore
 tsconfig.json
-.log
+.log
+.github