Update language information in dosagelib/languages.py.

def main():
    """Update language information in dosagelib/languages.py."""
    fn = os.path.join(basepath, 'dosagelib', 'languages.py')
    encoding = 'utf-8'
    with codecs.open(fn, 'w', encoding) as f:
        f.write('# -*- coding: %s -*-%s' % (encoding, os.linesep))
        f.write('# ISO 693-1 language codes from pycountry%s' % os.linesep)
        f.write('# This file is automatically generated, DO NOT EDIT!%s' % os.linesep)
        lang = get_used_languages()
        write_languages(f, lang)