Issue should be repeatable using a db.t3.small RDS instance running SQL Server Web Edition.
When running the CreateWeekliyMaintenanceJob.sql file (after running CreateDatabaseAndObjects.sql as stated), the following error can be observed:
Started executing query at Line 3
Msg 14515, Level 16, State 1, Procedure msdb.dbo.sp_add_job, Line 65
Only a member of the sysadmin server role can add a job for a different owner with @owner_login_name.
I think it would be great if the support article would include a note about version compatibility, or ideally this job could be written in a way that is cross-compatible across SQL Server editions.