Update ISSUE_TEMPLATE

.github/ISSUE_TEMPLATE

@@ -1,3 +1,8 @@
+<!--
+  Please post questions in Stack Overflow under the react-native-navigation tag
+  https://stackoverflow.com/questions/tagged/react-native-navigation
+-->
+
 ### Issue Description
 
 [ENTER DESCRIPTION HERE - Please make sure to use the current [naming conventions](https://github.com/wix/react-native-navigation/issues/197)]