build: add config for lock-threads bot

.github/lock.yml

@@ -0,0 +1,16 @@
+# Configuration for lock-threads - https://github.com/dessant/lock-threads
+
+# Number of days of inactivity before a closed issue or pull request is locked
+daysUntilLock: 7
+
+# Label to add before locking, such as `outdated`. Set to `false` to disable
+lockLabel: false
+
+# Comment to post before locking. Set to `false` to disable
+lockComment: >
+  This thread has been automatically locked since there has not been
+  any recent activity after it was closed. Please open a new issue for
+  related bugs.
+
+# Limit to only `issues` or `pulls`
+only: issues