Added issue template

Author: Bende Roland

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,20 @@
+
+---
+
+## Python Code
+```python
+
+YOUR CODE
+
+```
+
+## Command Line
+
+```console
+$ bigquery-migrations ... 
+```
+
+## Environment
+* Python version:
+* bigquery-migrations version:
+* Platform: windows, linux, macOSX, and other OS...