fix: ensure all oci auth secrets in values.yaml are created (#390)

## Description
Previously when adding multiple oci secrets, only the last secret added
to the values.yaml was being created. This change ensures that our
oci-auth template does not overwrite previous secrets.

Author: ahmad-ibra

chart/validator/templates/plugin-secret-oci-auth.yaml

@@ -7,4 +7,5 @@ stringData:
   {{- range $key, $val := .env }}
   {{ $key }}: {{ $val | quote }}
   {{- end }}
+---
 {{- end }}