AttributeError: 'ParsedRequirement' object has no attribute 'req' in PIP 21.1.1

Question

I am currently upgrading a project from Django 2.1 to Django 2.2. In doing so, I have been getting the following error when doing pip install -r requirements.txt.

Running command git clone -q git://github.com/user/djangocms-comments /tmp/pip-req-build-x00esn
u5 
        ERROR: Command errored out with exit status 1:
         command: /home/user/miniconda3/envs/python-3.6-test-web/bin/python -c 'import io, o
    s, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-x00esnu5/setup.py'"'"'; __file__='"
    '"'/tmp/pip-req-build-x00esnu5/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if o
    s.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read
    ().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_i
    nfo --egg-base /tmp/pip-pip-egg-info-xm4vt9bf                                                         
             cwd: /tmp/pip-req-build-x00esnu5/
        Complete output (7 lines):
        Traceback (most recent call last):
          File "<string>", line 1, in <module>
          File "/tmp/pip-req-build-x00esnu5/setup.py", line 188, in <module>
            install_requires = [str(ir.req) for ir in requirements]
          File "/tmp/pip-req-build-x00esnu5/setup.py", line 188, in <listcomp>
            install_requires = [str(ir.req) for ir in requirements]
        AttributeError: 'ParsedRequirement' object has no attribute 'req'
        ----------------------------------------

It appears that the package djangocms_comments is outdated in how it uses pip. I have gathered that much by searching this site. However, I am unsure how to fix this.

The error happens here. Any help or guidance would be appreciated.