Update Bug report form.yml

Author: victorhuangwq

.github/ISSUE_TEMPLATE/Bug report form.yml

@@ -74,7 +74,7 @@ body:
 - id: os
   type: dropdown
   attributes:
-    description: What operating system are you seeing this issue with?
+    description: Which operating system are you seeing this issue with?
     label: Operating System
     multiple: true
     options: