Add warnOnImplicitThis: true

Author: Dave Bartolomeo

actions/ql/extensions/immutable-actions-list/qlpack.yml

@@ -4,6 +4,7 @@
 name: github/immutable-actions-list
 version: 0.0.1-dev
 library: true
+warnOnImplicitThis: true
 extensionTargets:
   # We expect to need this model pack even after GA of Actions analysis, so make it compatible with
   # all future prereleases plus 1.x.x. We should be able to remove this back before we need to