Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
06:12:53                 out: failed with code 1 and output:
06:12:53                 out: Error: INSTALLATION FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
06:12:53                 out: redhat-postgresql-persistent:
06:12:53                 out: - image.tag: image.tag must be one of the following: "latest", "13-el9", "13-el8", "12-el8", "12"
06:12:53                 out: 
06:12:53                 out: 
Image tag does not exist in Helm chart values.json. Look at the definition of values.json file