Added issue template for GitHub

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,28 @@
+## Description
+
+[Description of the bug]
+
+### Expected behavior
+
+[What you expected to happen]
+
+### Actual behavior
+
+[What is actually happening]
+
+### Steps to reproduce the bug
+
+1. [First step]
+2. [Second step]
+3. [and so on...]
+
+### Package versions
+
+- Python: `python --version`
+- MkDocs: `mkdocs --version`
+- Material: `pip show mkdocs-material | grep -E ^Version`
+
+### System information
+
+- OS: [The operating system you're running]
+- Browser: [The browser used, if relevant]