AttributeError: '_NamespacePath' object has no attribute 'sort' on Read the docs

Pretty sure this isn't a dupe.

my read docs build fails here:

Collecting sphinxcontrib-inlinesyntaxhighlight==0.2 (from -r /home/docs/checkouts/readthedocs.org/user_builds/zproc/checkouts/latest/requirements.txt (line 33))
  Using cached https://files.pythonhosted.org/packages/5c/8b/17998fe9ebbec7e176f344648a86094d7b358e63d8f4593ae3dfbb9bb560/sphinxcontrib-inlinesyntaxhighlight-0.2.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/setuptools/__init__.py", line 10, in <module>
        from setuptools.extern.six.moves import filter, filterfalse, map
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/setuptools/extern/__init__.py", line 1, in <module>
        from pkg_resources.extern import VendorImporter
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3017, in <module>
        @_call_aside
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3003, in _call_aside
        f(*args, **kwargs)
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3045, in _initialize_master_working_set
        dist.activate(replace=False)
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2577, in activate
        declare_namespace(pkg)
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2151, in declare_namespace
        _handle_ns(packageName, path_item)
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2091, in _handle_ns
        _rebuild_mod_path(path, packageName, module)
      File "/home/docs/checkouts/readthedocs.org/user_builds/zproc/envs/latest/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2120, in _rebuild_mod_path
        orig_path.sort(key=position_in_sys_path)
    AttributeError: '_NamespacePath' object has no attribute 'sort'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-wlv3e5i4/sphinxcontrib-inlinesyntaxhighlight/
You are using pip version 9.0.1, however version 10.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

Looks like it is failing to install sphinxcontrib-inlinesyntaxhighlight, which installs just fine in my local machine.

A simple search seems to say that it can be fixed using pip install --upgrade pip setuptools, but I don't know how to do that on read the docs.

Here is the requirements.txt i supply to read the docs

alabaster==0.7.11
Babel==2.6.0
backcall==0.1.0
certifi==2018.4.16
chardet==3.0.4
decorator==4.3.0
docutils==0.14
idna==2.7
imagesize==1.0.0
ipython==6.4.0
ipython-genutils==0.2.0
jedi==0.12.1
Jinja2==2.10
MarkupSafe==1.0
packaging==17.1
parso==0.3.0
pexpect==4.6.0
pickleshare==0.7.4
pkginfo==1.4.2
prompt-toolkit==1.0.15
psutil==5.4.6
ptyprocess==0.6.0
Pygments==2.2.0
pyparsing==2.2.0
pytz==2018.5
pyzmq==17.0.0
requests==2.19.1
requests-toolbelt==0.8.0
simplegeneric==0.8.1
six==1.11.0
snowballstemmer==1.2.1
Sphinx==1.7.5
sphinxcontrib-inlinesyntaxhighlight==0.2
sphinxcontrib-websupport==1.1.0
tblib==1.3.2
tinydb==3.9.0.post1
tqdm==4.23.4
traitlets==4.3.2
twine==1.11.0
urllib3==1.23
wcwidth==0.1.7