Missing `gin upload` documentation details

[JuliaSprenger]

When running gin upload <filename> it is not clear from the documentation that this operation includes a gin commit <filename>. E.g. gin upload --help yields the following example, indicating only previously committed changes will be uploaded.

Examples:

  Upload all previously committed changes to remote named 'labdata'
    $ gin upload --to labdata

I think the documentation should clearly state, that gin upload runsgin commit first.

This issue refers to the GIN command line client 1.11 Build 001459 (103e923)