Collection parameters cannot be last

[YaroslavKormushyn]

The --channels parameter accepts a list of conda package channels, so we cannot pass the channels as the last parameter before the actual files. We either need to add this to the help page and docs or improve the parameter passing in order to have it independent of order.

Example:

> conda press --skip-python --subdir win-64 --channels ifcopenshell ifcopenshell=0.7.0
conda-press: error: the following arguments are required: files

[YaroslavKormushyn]

Ok, this applies to any list parameter - it will always think that the actual files to build wheels from are part of the previous list parameter input.