Add support for UFOZ as input format when no -u flag is used

[NightFurySL2001]

Resolves #887 .

[anthrotype]

thank you! I thought it was already supported, but it seems like it wasn't :)
could you also add a little test please?

[NightFurySL2001]

Sorry, I am quite new to contributing and am not sure on how to add tests 😅

[anthrotype]

no worries.

can you please fix the linter errors here:
https://github.com/googlefonts/fontmake/runs/7042616527?check_suite_focus=true

the autoformatter (black) is complaining about line length or something.
You can install black and run on the modified files and the linter error should go away

[anthrotype]

out of curiosity, does it work if you run fontmake -u MyFont.ufoz (with the -u flag) instead of without -u (implicit format guessed from positional arguments' file extension)? I thought that would already work.

I'm still ok to accept a patch like yours, just wanted to confirm that.

[anthrotype]

isort is now complaining about the order of imports, sorry.

+import os
 import sys
-import os

[NightFurySL2001]

Yeah, using -u did work. It's just that it's not that easy to use lol
I'll fix the import too.

[NightFurySL2001]

Also just a suggestion, might be better to provide the option to export .ufoz in future too. It's quite a pain in butt to export individual UFO folders for CJK fonts when one of them can easily surpass 10k+ glyphs. (and interpolating variable fonts... urgh)

[anthrotype]

might be better to provide the option to export .ufoz

yeah, sounds good. Would you like to work on that in this same PR?

[NightFurySL2001]

Not really, I have no idea on how to do this...

[anthrotype]

ok that's fine. We can keep #887 open until that's done. So this PR here only adds support for reading .ufoz when passed in to the fontmake CLI without the explicit -u flag.
What's left to do for #887 is also allow ufoz as an additional output format for -o option. That would only be relevant for .glyphs inputs, of course (i.e. if one wants to convert a .glyphs file to a Designspace file + a set of .ufoz masters).

[NightFurySL2001]

Ok thank you.