Add duplicate checkbox to issue templates (#480)

* Update bug_report.yml

* Update feature_request.yml

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -78,3 +78,10 @@ body:
       options:
         - label: I've confirmed the issue exists on the latest version of YimMenuV2
           required: true
+  - type: checkboxes
+    attributes:
+      label: Duplicate
+      description: You confirm that you've read existing open issues of YimMenuV2 and this isn't a duplicate of an already existing bug.
+      options:
+        - label: I confirm that issue isn't a duplicate.
+          required: true

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -32,4 +32,11 @@ body:
 
         Tip: You can attach images or log files by clicking this area to highlight it and then dragging files in.
     validations:
-      required: false
+      required: false
+  - type: checkboxes
+    attributes:
+      label: Duplicate
+      description: You confirm that you've read existing open issues of YimMenuV2 and this isn't an existing feature request.
+      options:
+        - label: I confirm that issue isn't a duplicate.
+          required: true