Make the issue template work (lightbend#791)

Author: ennru

.github/ISSUE_TEMPLATE/---bug-report.md

@@ -1,5 +1,6 @@
 ---
 name: "\U0001F41B Bug report"
+about: "Note the maintenance ambition for this library."
 ---
 
 This library is considered feature complete. We will make sure "Typesafe Config" keeps up with future JVM versions, but will rarely make any other changes.