unicode characters break help output

It seems some of the help text for snapcraft includes unicode quotation marks which breaks the output of 'snapcraft help'

root@snappy-dev:/home/ubuntu/snapcraft-2.3/snappy# snapcraft help plugins
'ascii' codec can't encode character '\u2019' in position 3253:
ordinal not in range(128)

as well as --help
root@snappy-dev:/home/ubuntu/snapcraft-2.3/snappy# snapcraft --help
Traceback (most recent call last):
  File "/usr/bin/snapcraft", line 31, in <module>
    snapcraft.main.main()
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 106, in main
    args = docopt(__doc__, version=_get_version(), options_first=True)
  File "/usr/lib/python3/dist-packages/docopt.py", line 575, in docopt
    extras(help, version, argv, doc)
  File "/usr/lib/python3/dist-packages/docopt.py", line 481, in extras
    print(doc.strip("\n"))
UnicodeEncodeError: 'ascii' codec can't encode character '\u201c' in position 676: ordinal not in range(128)