Update issue_template.md

Author: iyegoroff

.github/issue_template.md

@@ -1 +1,3 @@
-<!-- Please specify your mobile platform(s) and react-native & react-native-text-gradient versions. -->
+<!-- Please specify your mobile platform(s) and react-native & react-native-text-gradient versions. Also check [here](https://github.com/iyegoroff/react-native-text-gradient#status) if your rntg version corresponds with your rn version.-->
+
+<!-- Getting "No ViewManager defined for class X" error most likely means that something is wrong with your build and/or configuration. Try cleaning the project and check if your configuration matches with [manual installation](https://github.com/iyegoroff/react-native-text-gradient/blob/master/manual_installation.md) instruction. -->