Does not build on Travis CI Windows : "UnicodeDecodeError: 'charmap' codec can't decode byte 0x8f in position 612: character maps to <undefined>"

[nicobo]

The first error "python3: command not found" should be ok since we try with "python" after that.

$ bash -c 'echo $BASH_VERSION'
4.4.23(1)-release
before_install.1
40.27s$ choco install python --version 3.8.0
before_install.2
6.00s$ python -m pip install --upgrade pip
0.68s$ python3 setup.py build || python setup.py build
The command "python3 setup.py build || python setup.py build" failed and exited with 1 during .
Your build has been stopped.
/c/Users/travis/.travis/functions: line 109: python3: command not found
Traceback (most recent call last):
  File "setup.py", line 7, in <module>
    long_description = fh.read()
  File "C:\Python38\lib\encodings\cp1252.py", line 23, in decode
    return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x8f in position 612: character maps to <undefined>