Building from source requires specifying a tag env var

[thewhaleking]

Because of this:

py-scale-codec/setup.py

Lines 34 to 45 in f676638

	if environ.get('TRAVIS_TAG'):
	version = environ['TRAVIS_TAG'].replace('v', '')
	elif environ.get('CI_COMMIT_TAG'):
	version = environ['CI_COMMIT_TAG'].replace('v', '')
	elif environ.get('GITHUB_REF'):
	if not environ['GITHUB_REF'].startswith('refs/tags/v'):
	raise ValueError('Incorrect tag format {}'.format(environ['GITHUB_REF']))
	version = environ['GITHUB_REF'].replace('refs/tags/v', '')
	else:
	raise ValueError('Missing commit tag, can\'t set version')

to build from source, you must supply a tag via ENV VAR. This is unideal.