Add configuration for probot-stale bot (testcontainers#907)

* Add configuration for probot-stale bot

* Update stale.yml

.github/stale.yml

@@ -0,0 +1,23 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 90
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 14
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - pinned
+  - security
+  - "resolution/acknowledged"
+# 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. If you believe
+  this is a mistake, please reply to this comment to keep it open. If there isn't 
+  one already, a PR to fix or at least reproduce the problem in a test case will 
+  always help us get back on track to tackle this.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: >
+  This issue has been automatically closed due to inactivity. We apologise if
+  this is still an active problem for you, and would ask you to re-open the 
+  issue if this is the case.