docs(maintainers): link bug report template

Author: heitorlessa

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -7,6 +7,8 @@ body:
     attributes:
       value: |
         Thank you for submitting a bug report. Please add as much information as possible to help us reproduce, and remove any potential sensitive data.
+
+        Please become familiar with [our definition of bug](MAINTAINERS.md#is-that-a-bug).
   - type: textarea
     id: expected_behaviour
     attributes: