Daniel/add readme testing info

[daniel-cohere]

This pull request adds a new section to the README.md file, providing instructions for running tests locally. The section includes the necessary steps to set up the testing environment and execute the tests.

Changes:

• Added a new section titled "Running tests locally".
• Included installation commands for testing dependencies: pip install pytest pytest-asyncio pytest-mock requests-mock.
• Added instructions to install the project locally: pip install -e ..
• Provided the command to run the tests: pytest -sv tests/test_compass_client.py.

[benrules3]

Thanks for updating!