Replace awesome-slugify with python-slugify
The former drags us from getting update with new libraries (e.g
Unidecode).
pytz==2018.4 # https://github.com/stub42/pytz
-awesome-slugify==1.6.5 # https://github.com/dimka665/awesome-slugify
+python-slugify==1.2.5 # https://github.com/un33k/python-slugify
Pillow==5.1.0 # https://github.com/python-pillow/Pillow
{%- if cookiecutter.use_compressor == "y" %}
rcssmin==1.0.6{% if cookiecutter.windows == 'y' %} --install-option="--without-c-extensions"{% endif %} # https://github.com/ndparker/rcssmin
