Move GitHub bug report template to new format

Author: gilmoreorless

.github/issue_template.md renamed to .github/ISSUE_TEMPLATE/bug_report.md

@@ -1,10 +1,15 @@
+---
+name: Bug report
+about: Report a bug in timezone-related functionality
+---
+
 ### Environment
 
 <!--
-	If you're creating a bug report, please fill in this section.
+	When creating a bug report, please fill in this section.
 	It's much easier to diagnose the problem when the correct information is provided.
 
-	NOTE: Many issues are resolved if you just upgrade to the latest version.
+	NOTE: Many issues are resolved if you just upgrade to the latest version first.
 -->
 
 For bug reports, please run the following code in your environment and include the output: