Updated ISSUE_TEMPLATE

Removed the word "Core". It is only .NET 6.

Author: ckadluba

.github/ISSUE_TEMPLATE.md

@@ -14,7 +14,7 @@ If you are opening a feature request, you can ignore this template. Bug reports
 
 >> Target framework and operating system:
 
-[ ] .NET Core 6
+[ ] .NET 6
 [ ] .NET Framework 4.8
 [ ] .NET Framework 4.7
 [ ] .NET Framework 4.6