Sublime Text environment variables not present

I have installed yapf and the PyYapf package (https://github.com/jason-kane/PyYapf) for sublime text for Python code formatting. Furthermore, for my Python projects I'm using pipenv.

When executing the formatting command in sublime I receive the following error

Traceback (most recent call last):
  File "~/.pyenv/versions/3.6.8/bin/pipenv", line 10, in <module>
    sys.exit(cli())
  File "~/.pyenv/versions/3.6.8/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "~/.pyenv/versions/3.6.8/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 696, in main
    _verify_python3_env()
  File "~/.pyenv/versions/3.6.8/lib/python3.6/site-packages/pipenv/vendor/click/_unicodefun.py", line 124, in _verify_python3_env
    ' mitigation steps.' + extra
RuntimeError: Click will abort further execution because Python 3 was configured to use ASCII as encoding for the environment. Consult https://click.palletsprojects.com/en/7.x/python3/ for mitigation steps.

This system supports the C.UTF-8 locale which is recommended.
You might be able to resolve your issue by exporting the
following environment variables:

    export LC_ALL=C.UTF-8
    export LANG=C.UTF-8 

I have now tried the suggestion to use the two above exports and set them globally in my profile (and reboot). Opening a terminal and checking they seem to be available:

$printenv | grep "C.UTF-8"
LC_ALL=C.UTF-8
LANG=C.UTF-8

However, sublime text still gives the original error. Looking at the source of the package the environment is read in like this inside the PyYapf.py package:

self.popen_env = os.environ.copy()

When printing the content of self.popen_env then the LANG and LC_ALL don't seem to be set or not to the C.UTF-8 value.

Where is sublime text getting the envs from?

from Sublime Text environment variables not present