Accept file names with . replaced with _

[di]

Fixes #10030.

[di]

I've filed #14156 to eventually handle the inverse of this via a deprecation period.

[takluyver]

I think there's a corner case where this could go wrong with a project name like foo..bar or foo._bar. The spec says this normalises to foo_bar, but I think this implementation will give foo__bar (double underscore). If the wheel filename is already normalised, it won't match, so the upload would incorrectly be rejected.

This is probably pretty academic, though - I doubt anyone wants to use a name like that.

[di]

@takluyver Good call! See #14172 which should fix this.