Helper to run tests in different python versions

[derlih]

Is your feature request related to a problem?

Add helper targets to the Makefile that allow to run the test using the specific version of python and environment (AIOHTTP_NO_EXTENSIONS)

Describe the solution you'd like

Introduce new targets:

• test-3.7
• test-3.7-no-extensions

and so on.

It will make easier to check locally the problems occurred during CI on the python versions that are not installed locally.

Describe alternatives you've considered

Run the required steps manually.

Related component

Server, Client

Additional context

No response

Code of Conduct

• I agree to follow the aio-libs Code of Conduct

[webknjaz]

Personally, I'd prefer to have tox for this but I know that Andrew doesn't like it.

[derlih]

I just need a single command to run it. I don't care much how it would work. Would it use docker, tox or other tools.
For instance I had some failing tests for 3.7 and I'm not able to install it on my PC via package manager, I've started to search how to run it. Then I realized, that it's not the first time I'm doing it :-)
That's why I've created this ticket and PR #6132 .