Ansible 2.9 support

[micah]

Hello,

It seems that Ansible 2.9 is supported by mitogen (#674). https://mitogen.networkgenomics.com/ansible_detailed.html#noteworthy-differences says:

Ansible 2.3-2.8 are supported along with Python 2.6, 2.7, 3.6 and 3.7. Verify your installation is running one of these versions by checking ansible --version output.

Perhaps this information should be updated to indicate that mitogen does support Ansible 2.9?

[s1113950]

There's a PR out to change this: #714 unfortunately the tests are in bad shape and I don't have permissions to merge PRs if tests are failing 😞 I've been focusing on Ansible 2.10 support since that came out and haven't gotten around to fixing tests for other PRs yet.

[agowa]

Ticket for Ansible 2.10 support: #731