pgdg13 workaround

Author: pdurbin

doc/release-notes/6.10-release-notes.md

@@ -303,6 +303,8 @@ Java 21 is now required to run Dataverse. Solr can run under Java 17 or Java 21
 
    `sudo dnf install java-21-openjdk`
 
+   Note: if you see something like `Error: Failed to download metadata for repo 'pgdg13'`, you are probably still on PostgreSQL 13 and should upgrade, as explained in the End-Of-Life (EOL) note above. A workaround is to disable that repo with `sudo dnf config-manager --set-disabled pgdg13`.
+
 1. Set Java 21 as the default.
 
    Assuming you are using RHEL or a derivative such as Rocky Linux: