Publishes GitHub templates to simplify issue reporting and contributions

.github/ISSUE_TEMPLATE/bug.md

@@ -0,0 +1,38 @@
+---
+name: Bug report
+about: Create a report to help us improve Thunderbird User.JS
+title: "[BUG] "
+labels: 'bug'
+assignees: ''
+
+---
+
+**Describe the bug**
+<!-- A clear and concise description of what the bug is. -->
+
+
+**Expected behavior**
+<!-- A clear and concise description of what you expected to happen. -->
+
+
+**Screenshots**
+<!-- If applicable (i.e. graphical glitch), add screenshots to help explain your problem. -->
+
+
+**Environment**
+<!-- Please complete the following information: -->
+- Thunderbird version used (X.Y.Z) : 
+- `thunderbird user.js` template version used (X.Y or commit SHA) : 
+- Operating system and version : 
+- \[IF RELEVANT\] Graphical environment name and version : 
+
+
+**Additional context**
+<!-- If applicable, add any other context about the problem here. -->
+
+
+**Checklist**
+<!--- Put an `X` in all the boxes that apply : -->
+- [ ] I can confirm the bug is due to `thunderbird user.js` **template** and not an overridden preference nor an add-on ;
+- [ ] I have searched for `[SETUP-*]` tags and read them up ;
+- [ ] I have searched the GitHub project (issues and Wiki) for my issue.