added issue template

Author: cemde

.github/issue_template.md

@@ -0,0 +1,22 @@
+## Type
+
+- [ ] Bug
+- [ ] Feature request
+- [ ] Question
+
+## Summary
+
+<!-- One-sentence description -->
+
+## Details
+
+<!--
+For bugs: Steps to reproduce, expected vs actual behavior
+For features: Motivation and proposed design
+For questions: Context and what you've tried
+-->
+
+## Environment (if applicable)
+
+- maseval version:
+- Python version: