Update ISSUE_TEMPLATE.md

Author: allenhwkim

ISSUE_TEMPLATE.md

@@ -4,7 +4,7 @@ _Please be specific with an example. An issue with no example or unclear require
 **Steps to reproduce and a minimal demo**
 
   - _What steps should we try in your demo to see the problem?_
-  - _Plunker example(required)_ 
+  - _Plunker example(required), MCVE(Minimal/Complete/Verifable Example)_ 
   - _If you cannot reproduce an issue with a plunker example, it may be your environmental issue_
 
 **Current behavior**