chore: add "Did you customize Shield?"

Author: kenjis

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -82,6 +82,16 @@ body:
     validations:
       required: true
 
+  - type: textarea
+    id: shield-customization
+    attributes:
+      label: Did you customize Shield?
+      description: |
+        If "Yes," please tell us which classes you customized and how.
+        If "No," please indicate "No."
+    validations:
+      required: true
+
   - type: textarea
     id: description
     attributes: