build(requirements): cleanup dev-requirements.txt and make python2 co…

…mpatible

dev-requirements.txt

@@ -1,37 +1,9 @@
-alabaster==0.7.12
-atomicwrites==1.3.0
-attrs==19.1.0
-Babel==2.6.0
-bleach==3.1.0
-certifi==2019.3.9
-chardet==3.0.4
 coverage==4.5.3
-docutils==0.14
 euclid3==0.1
-idna==2.8
-imagesize==1.1.0
-Jinja2==2.10
-MarkupSafe==1.1.1
-more-itertools==6.0.0
-packaging==19.0
-pkginfo==1.5.0.1
-pluggy==0.9.0
-py==1.8.0
-Pygments==2.3.1
-pyparsing==2.3.1
 pytest==4.3.1
 pytest-cov==2.6.1
-pytz==2018.9
-readme-renderer==24.0
-requests==2.21.0
-requests-toolbelt==0.9.1
-six==1.12.0
-snowballstemmer==1.2.1
 Sphinx==1.8.5
 sphinx-bootstrap-theme==0.6.5
 sphinxcontrib-fulltoc==1.2.0
 sphinxcontrib-websupport==1.1.0
-tqdm==4.31.1
 twine==1.13.0
-urllib3==1.24.1
-webencodings==0.5.1