adding bug report template

Author: lemire

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,24 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Ideally, you should provide a reproducible test case.
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Additional context**
+Add any other context about the problem here.
+
+**Note:** Bug reports should come with a test case or, at least, an analysis.
+
+**Automated tool policy**: If you use an automated tool (e.g., static analysis,
+LLM, etc.), you need to demonstrate an understanding of the issue you are raising. Usually, a bug is demonstrated by a test case. Do not copy-paste what a tool is telling you.