Update documentation for global.minio.enabled
Today when running the chart I got the following deprecation warnings, this commit will update the documentation to reflect the deprecation warnings.
minio:
Chart-local `enabled` property has been moved to global. Please remove `minio.enabled` from your properties, and set `global.minio.enabled` instead.
registry:
Chart-local configuration of Minio features has been moved to global. Please remove `registry.minio.enabled` from your properties, and set `global.minio.enabled` instead.