Usage instructions not correct

[bobvanmanen]

Expected Behaviour

Adobe I/O plugins should be installed as follows:

$ aio plugins:install @adobe/aio-cli-plugin-aem
$ aio aem:upload --help
USAGE
$ aio aem:upload -h http://myaeminstance -c admin:12345 myimage.jpg
...

This how other Adobe I/O CLI plugins are used.

Actual Behaviour

The README provides these usage instructions. These work, but not correct as noted above.

$ npm install -g @adobe/aio-cli-plugin-aem
$ aio-aem COMMAND
running command...
$ aio-aem (-v|--version|version)
@adobe/aio-cli-plugin-aem/1.0.3 darwin-x64 node-v10.16.3
$ aio-aem --help [COMMAND]
USAGE
  $ aio-aem COMMAND
...

[bobvanmanen]

Looks like this is prevalent across all aio-cli-plugin-* repositories.

[bobvanmanen]

Created a general ticket since this impacts most of the aio cli plugin repositories: adobe/aio-cli#189