Update unit tests requirements/units.txt path (#61656)

docs/docsite/rst/dev_guide/developing_modules_general.rst

@@ -266,7 +266,7 @@ Unit tests
 
 You can add unit tests for your module in ``./test/units/modules``. You must first setup your testing environment. In this example, we're using Python 3.5.
 
-- Install the requirements (outside of your virtual environment): ``$ pip3 install -r ./test/runner/requirements/units.txt``
+- Install the requirements (outside of your virtual environment): ``$ pip3 install -r ./test/lib/ansible_test/_data/requirements/units.txt``
 - To run all tests do the following: ``$ ansible-test units --python 3.5`` (you must run ``. hacking/env-setup`` prior to this)
 
 .. note:: Ansible uses pytest for unit testing.