Issue templates

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,21 @@
+---
+name: Bug report
+about: Topgrade might be misbehaving
+labels: is:bug
+---
+
+**What did you expect to happen?**
+...
+
+
+**What actually happened?**
+...
+
+
+**Additional details:**
+- Which operating system or Linux distribution are you using?
+- How did you install Topgrade?
+
+<details><pre>
+Paste the output of `topgrade -v`
+</pre></details>