Update issue templates

Author: thepassle

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,17 @@
+---
+name: Bug report
+about: Bug report
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Checklist**
+- [ ] Did you run the analyzer with the `--dev` flag to get more information?
+- [ ] Did you create a **minimal** reproduction in the [playground](https://custom-elements-manifest.netlify.app/)?
+
+Completing the items above will greatly improve triaging time of your issue.
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.