use dashes instead of underscores

[lev-blit]

the second part of python/typeshed#15550

[lev-blit]

@srittau once this merges I'll open the second PR for typeshed :)

[brianschubert]

There's also a fixture that needs to be updated here:

stub_uploader/tests/test_unit.py

Lines 314 to 317 in 24bf940

	({"upstream_repository": 12345}, None),
	({"upstream_repository": "https://[].foo.com"}, None),
	(
	{"upstream_repository": "https://github.com/psf/requests"},

[srittau]

Nice, thanks!