Remove old issue template

.github/ISSUE_TEMPLATE/issue-template.md

@@ -1,21 +0,0 @@
----
-name: Issue template
-about: Common things to fill
-title: "Issue in [Mobile, Desktop, Web]"
-labels: ''
-assignees: ''
-
----
-
-Please note that we are using <b>latest</b> flutter version in stable channel on branch master. If you are using beta or master channel, or you are not using <b>latest</b> flutter version in stable channel, you may experience error.
-
-<!-- Did you try the running `example` directory?? How does it goes -->
-
-<!-- Please explain how to encounter the issue in details if possible -->
-
-<!-- Don't forgot to mention the platform you are testing in -->
-
-<!-- Insert your images here if possible -->
-<!-- Images: -->
-
-<!-- Add short video that showcase the problem will help -->