Installing mkdocs-redirects mentions missing testresources

When installing mkdocs-redirects, a missing dependency "testresources" is mentioned. Usage of mkdocs-redirects seems not to affected, but would be nice not having this error message.

$ pip --version
pip 21.3.1 from /usr/local/lib/python3.8/dist-packages/pip (python 3.8)

// Ensure cache is empty
$ pip cache purge

$ pip install mkdocs-redirects
Defaulting to user installation because normal site-packages is not writeable
Collecting mkdocs-redirects
  Downloading mkdocs-redirects-1.0.3.tar.gz (5.1 kB)
  Preparing metadata (setup.py) ... done
Collecting mkdocs<2,>=1.0.4
  Downloading mkdocs-1.2.3-py3-none-any.whl (6.4 MB)
     |████████████████████████████████| 6.4 MB 3.0 MB/s            
[...]
Successfully built mkdocs-redirects
Installing collected packages: six, zipp, python-dateutil, MarkupSafe, watchdog, pyyaml-env-tag, packaging, mergedeep, Markdown, Jinja2, importlib-metadata, ghp-import, mkdocs, mkd
ocs-redirects

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
launchpadlib 1.10.13 requires testresources, which is not installed. // <!---------------------------------------------------------

Successfully installed Jinja2-3.0.3 Markdown-3.3.4 MarkupSafe-2.0.1 ghp-import-2.0.2 importlib-metadata-4.8.2 mergedeep-1.3.4 mkdocs-1.2.3 mkdocs-redirects-1.0.3 packaging-21.2 python-dateutil-2.8.2 pyyaml-env-tag-0.1 six-1.16.0 watchdog-2.1.6 zipp-3.6.0

mkdocs / mkdocs-redirects

Installing mkdocs-redirects mentions missing testresources #31