wheel: Wheel 0.34 broke installing from sdist in docker (UnicodeEncodeError)

We download wheel as a sdist and install it into a venv inside a docker container. As of 0.34, something changed so that we get a UnicodeDecodeError. Perhaps a unicode character slipped into a README or CHANGELOG? I’ll try to get more details as I track it down further, but since wheel 0.34 was just released 4 hours ago, I wanted to get this report in as soon as I could.

954 pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-6gct78aj/overlay --no-warn-script-location --no-binary :all: -i https://pypi.org/simple -- setuptools wheel
955        cwd: None
956   Complete output (27 lines):
957   Collecting setuptools
958     Downloading setuptools-45.1.0.zip (859 kB)
959   Collecting wheel
960     Downloading wheel-0.34.0.tar.gz (60 kB)
961   ERROR: Exception:
962   Traceback (most recent call last):
963     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/cli/base_command.py", line 186, in _main
964       status = self.run(options, args)
965     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/commands/install.py", line 331, in run
966       resolver.resolve(requirement_set)
967     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/legacy_resolve.py", line 177, in resolve
968       discovered_reqs.extend(self._resolve_one(requirement_set, req))
969     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/legacy_resolve.py", line 333, in _resolve_one
970       abstract_dist = self._get_abstract_dist_for(req_to_install)
971     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/legacy_resolve.py", line 282, in _get_abstract_dist_for
972       abstract_dist = self.preparer.prepare_linked_requirement(req)
973     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 482, in prepare_linked_requirement
974       hashes=hashes,
975     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 287, in unpack_url
976       hashes=hashes,
977     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 164, in unpack_http_url
978       unpack_file(from_path, location, content_type)
979     File "].tox/bundle/lib/python3.6/site-packages/pip/_internal/utils/unpacking.py", line 261, in unpack_file
980       untar_file(filename, location)
981     File ".tox/bundle/lib/python3.6/site-packages/pip/_internal/utils/unpacking.py", line 222, in untar_file
982       with open(path, 'wb') as destfp:
983   UnicodeEncodeError: 'ascii' codec can't encode characters in position 72-74: ordinal not in range(128)