Create issue templates (#1173)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,29 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: 'Status: Open, Type: Bug'
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+```c++
+#include <gsl>
+
+// your repro here: ...
+```
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Spec (please complete the following information):**
+ - OS: [e.g. Windows]
+ - Compiler: [e.g. MSVC]
+ - C++ Version: [e.g. C++20]
+
+**Additional context**
+Add any other context about the problem here.