Add bug report template

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,33 @@
+---
+name: Bug report
+about: 'Report an unexpected behavior '
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+### Description
+
+Describe your issue in details, provide error logs or screenshots if possible.
+
+### Your environment
+
+- OS or distribution (e.g. Arch Linux, macOS 10.15, Windows 7...)
+- Architecture (e.g. x86 64bit)
+- How did you install Mirage? (e.g. manual, AppImage, Flatpak...)
+- For manual installations: your Qt version
+- For manual installations: your Python version
+
+### Steps to reproduce
+
+1. Do this...
+2. Do that...
+
+### Expected behavior
+
+Tell us what should happen
+
+### Actual behavior
+
+Tell us what happens instead