chore: ADD ISSUE_TEMPLATE

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,16 @@
+<!--
+Make sure you searched for existing issues that already report this problem.
+-->
+
+### What's the problem?
+
+### How to reproduce it ?
+1.
+2.
+3.
+
+### Environment
+- Browser:
+- Browser version:
+- Violentmonkey version:
+- OS: