Improve wording of requirements/README.md

Co-Authored-By: Leopold Talirz <leopold.talirz@gmail.com>

requirements/README.md

@@ -1,7 +1,7 @@
 # README
 
-The `requirements-*.txt` files within this directory describe a working set of Python requirements that are used to setup the Python environment for all supported Python versions to execute the automated tests for this package. While possible, they are not meant to be used as the primary mechanism to create a Python environment to install this package. For instructions on how to install the package, please see documentation.
+The `requirements-*.txt` files within this directory define the Python environment used for the *continuous integration tests* of this package. Note: For instructions on how to install the package for regular use, please see the documentation.
 
-The requirements defined here must be consistent with the package dependencies defined in the `setup.json` file. The consistency is automatically checked as part of the continuous integration of this package.
+The consistency of the requirements defined here with the dependencies defined in the `setup.json` file is checked automatically as part of the continuous integration workflow.
 
 https://github.com/aiidateam/aiida-core/wiki/AiiDA-Dependency-Management