typo: happend -> happened (#375)

Author: kaovilai

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -20,16 +20,16 @@ body:
     attributes:
       label: Describe bug
       description: and also tell us how to reproduce!
-      placeholder: A bug happend when I ate cereal!
-      value: "A bug happend when I ate cereal!"
+      placeholder: A bug happened when I ate cereal!
+      value: "A bug happened when I ate cereal!"
     validations:
       required: true
   - type: textarea
     id: what-happened
     attributes:
       label: What happened?
       description: Also tell us, what did you expect to happen?
-      placeholder: A bug happend!
+      placeholder: A bug happened!
       value: "A bug happened!"
     validations:
       required: true