Fix readthedocs documentation generation

[zhindes]

• This contribution adheres to CONTRIBUTING.md.

What does this Pull Request accomplish?

It fixes readthedocs generation.

Why should this Pull Request be merged?

readthedocs has been failing for some time with this error:

Sphinx version error:
The sphinxcontrib.applehelp extension used by this project needs at least Sphinx v5.0; it therefore cannot be built with this version.

Closes #487

What testing has been done?

Manually generating the documentation works. RTD pipeline seems happy.

[github-actions]

Test Results

 10 files   -     20   10 suites   - 20   2m 51s ⏱️ - 30m 53s
 95 tests  -  1 147   95 ✅  -    967  0 💤  -   180  0 ❌ ±0 
950 runs   - 18 310  950 ✅  - 15 690  0 💤  - 2 620  0 ❌ ±0 

Results for commit 2220e93. ± Comparison against base commit 908cebf.

This pull request removes 1147 tests.

tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path0]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path10]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path11]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path12]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path13]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path14]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path15]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path16]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path17]
tests.acceptance.test_examples ‑ test___shipping_example___run___no_errors[library_init_kwargs-example_path1]
…