correct S3 configuration in 471?

[lozbrown]

As it stands the legacy config produces the following warnings:

1. Configuration property 'hive.s3.endpoint' is deprecated since 470 and will be removed in the future
2. Configuration property 'hive.s3.path-style-access' is deprecated since 470 and will be removed in the future
3. Configuration property 'hive.s3.region' is deprecated since 470 and will be removed in the future

however attempting to use the newer config EG

  flex: |-
    connector.name=storage
    fs.native-s3.enabled=true
    s3.endpoint=https://s3-eu-west-2.amazonaws.com
    s3.path-style-access=true
    s3.region=eu-west-2

produces errors like:

io.airlift.bootstrap.ApplicationConfigurationException: Configuration errors:

1. Error: Configuration property 'fs.native-s3.enabled' was not used
2. Error: Configuration property 's3.endpoint' was not used
3. Error: Configuration property 's3.path-style-access' was not used
4. Error: Configuration property 's3.region' was not used

As has been mentioned many times, some example config in the readme of this project would be very helpful

[nineinchnick]

Native FS is not supported yet, there's another issue about it: #282

Can you open a PR to add some examples in the readme?