Add bug report template

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,38 @@
+---
+name: Bug report
+about: Create a report to help us improve
+
+---
+
+<!--
+IMPORTANT: we are not accepting issues about Termux
+installations running on Android 5.x-6.x.
+-->
+
+**Problem description**
+<!--
+A clear and concise description of what the problem is.
+You may post screenshots in addition to description.
+Provide output from running your command in verbose mode, i.e.
+`proot -v 9 your-cmd-here`, or export the env var
+`PROOT_VERBOSE=9` before running a script.
+-->
+
+**Steps to reproduce**
+<!--
+Steps to reproduce the behavior. Please post all necessary
+commands that are needed to reproduce the issue.
+-->
+
+**Expected behavior**
+<!--
+A clear and concise description of what you expected to happen.
+-->
+
+**Additional information**
+<!--
+Post output of command 'termux-info' between '```' (code formatting).
+-->
+```
+
+```