Website docs instruct new users to download v2.9

[tim-seoss]

The getting started docs at: https://mitogen.networkgenomics.com/ansible_detailed.html instruct the user to:

"Download and extract https://networkgenomics.com/try/mitogen-0.2.9.tar.gz"

... these instructions are pointed to by the README.md in the root of the git repo:

[Please see the documentation](https://mitogen.networkgenomics.com/)

[moreati]

Duplicate of #962