Fix minio persistence storageClassName

[upiksaleh]

What kind of change does this PR introduce?

Bug fix

What is the current behavior?

minio persistence from values always use default storageClass

spec:
  {{- if .Values.minio.persistence.minioClassName }}
  minioClassName: {{ .Values.minio.persistence.minioClassName }}
  {{- end }}

What is the new behavior?

spec:
  {{- if .Values.minio.persistence.storageClassName }}
  storageClassName: {{ .Values.minio.persistence.storageClassName }}
  {{- end }}

[take-cheeze]

Thank you for fix!
This seems to be caused by copy paste and simple text replacing.
I've confirmed this changed fixed the storage class of my minio pod.