Update supported versions on issue template

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

.github/ISSUE_TEMPLATE/BUG_REPORT.yml

@@ -76,9 +76,9 @@ body:
         Select Nextcloud Server version.
         _Versions not listed here are not maintained and not supported anymore_
       options:
-        - "25"
         - "26"
         - "27"
+        - "28"
         - "master"
     validations:
       required: true