[diffoscope] |pip install diffoscope| fails

[Mike Grunweg]

Hi,

on my system, trying to install diffoscope using pip fails.

STR:
1. Create a new virtualenv, e.g. with |virtualenv TEMP|.
2. Activate the virtualenv, e.g. with |source TEMP/bin/activate|.
3. Run |pip install diffoscope| (in the very same terminal, i.e. in the
virtualenv just activated).

Expected results:
Diffoscope is installed successfully and read to use.

Actual results: Installation fails. I get the following log output

$ pip install diffoscope
Collecting diffoscope
  Downloading diffoscope-86.tar.gz (969kB)
    100% |████████████████████████████████| 972kB 581kB/s
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-Ii2qtN/diffoscope/setup.py", line 31, in <module>
        long_description=open('README.rst', encoding='utf-8').read(),
    TypeError: 'encoding' is an invalid keyword argument for this function
   
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in
/tmp/pip-build-Ii2qtN/diffoscope/

(Trying to run |diffoscope| confirms that diffoscope was indeed not
installed successfully.)

Reproduced on Debian jessie. The directory the virtualenv was created in
contains only ASCII characters.
Let me know if I there is anything else I can do. Any help is
appreciated. Thanks!

~Mike