Update app_request.yaml

.github/ISSUE_TEMPLATE/app_request.yaml

@@ -1,6 +1,6 @@
 name: "App Request"
 description: "Request to add an app to the app store."
-title: "[App Request]: AppName"
+title: "[App Request] AppName"
 labels: ["App Request"]
 body:
   - type: markdown