Repository configuration not possible at project level

[lukaszmoroz]

• I have searched the issue tracker and believe that this is not a duplicate.

Make sure you run commands with -v flag before pasting the output.

Steps to reproduce

$ pdm config --local repository.foo.url "https://pypi.org/simple"
$ pdm config --local repository.foo.username "foo"

$ pdm config
[...]
repository.foo.url = https://pypi.org/simple
repository.foo.username = foo

Actual behavior

This is not possible despite what the documentation says (introduced here: ac63d76)

Expected behavior

Should work the same as pypi.* configs or documentation should be fixed if its not meant to be supported.

Apparently this was rejected at some point (#1309) but since then a lot changed in the way pypi indexes are configured, so consider making repository.* work the same way.