Merge pull request #1532 from OneSignal/add_ios_18_to_issues_template

[templates] add ios `18` to bug report template

Author: nan-li

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -53,6 +53,7 @@ body:
       description:  Which versions of iOS are broken for you?
       multiple: true
       options:
+        - "18"
         - "17"
         - "16"
         - "15"