Unable to complete vagrant setup (pymavlink)

[atownnoob]

bionic64: Collecting pymavlink
bionic64: Downloading pymavlink-2.4.34.tar.gz (10.6 MB)
bionic64: Installing build dependencies: started
bionic64: Installing build dependencies: finished with status 'done'
bionic64: Getting requirements to build wheel: started
bionic64: Getting requirements to build wheel: finished with status 'error'
bionic64: ERROR: Command errored out with exit status 1:
bionic64: command: /usr/bin/python /home/vagrant/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpjKoh9h
bionic64: cwd: /tmp/pip-install-52VoQ2/pymavlink
bionic64: Complete output (16 lines):
bionic64: Traceback (most recent call last):
bionic64: File "/home/vagrant/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 280, in
bionic64: main()
bionic64: File "/home/vagrant/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 263, in main
bionic64: json_out['return_val'] = hook(**hook_input['kwargs'])
bionic64: File "/home/vagrant/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 114, in get_requires_for_build_wheel
bionic64: return hook(config_settings)
bionic64: File "/tmp/pip-build-env-mw4XbY/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 146, in get_requires_for_build_wheel
bionic64: return self._get_build_requires(config_settings, requirements=['wheel'])
bionic64: File "/tmp/pip-build-env-mw4XbY/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 127, in _get_build_requires
bionic64: self.run_setup()
bionic64: File "/tmp/pip-build-env-mw4XbY/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 142, in run_setup
bionic64: exec(compile(code, file, 'exec'), locals())
bionic64: File "setup.py", line 108, in
bionic64: with open("README.md", "r", encoding = "utf-8") as fh:
bionic64: TypeError: 'encoding' is an invalid keyword argument for this function
bionic64: ----------------------------------------
bionic64: ERROR: Command errored out with exit status 1: /usr/bin/python /home/vagrant/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpjKoh9h Check the logs for full command output.

[atownnoob]

Apologies that I haven't followed the contributing guidelines. Next item will be in accordance with the guidelines.
To put a small summary - I have been following the technical documents for Windows SITL (https://ardupilot.org/dev/docs/setting-up-sitl-using-vagrant.html). Issue occurs at Step 4, "vagrant up". Unable to complete the environment build, with the issue listed above.

[atownnoob]

Closed, issue as described in pymavlink bug: ArduPilot/pymavlink#724