Describe the bug
Both README.rst and CONTRIBUTING.rst contain sections on running tests. They appear to be contradictory. Wouldn't it make sense to remove that section from README.rst and update and/or elaborate CONTRIBUTING.rst?

Checklist

• I have reproduced in environment where pip check passes without errors
• I have provided pip freeze results
• I have provided sample code or detailed way to reproduce
• I have tried the same code in botocore to ensure this is an aiobotocore specific issue
• I have tried similar code in aiohttp to ensure this is is an aiobotocore specific issue
• I have checked the latest and older versions of aiobotocore/aiohttp/python to see if this is a regression / injection

pip freeze results

Environment:

• Python Version: [e.g. 3.6]
• OS name and version: [e.g. darwin stretch]

Additional context
Add any other context about the problem here.