Allow to specify version of python-virtualenv in .travis.yml (with language: generic)

[ale5000-git]

In .travis.yml inside addons => apt => packages => python-virtualenv (with language: generic) it allow only the default version of it, if I specify a different version it fails.

I need to change to older/newer versions to test (with sudo: false) different versions of Python not supported by default.
Can you please allow it?

It is important to map to a specific version because an update to python-virtualenv can break my testing code.

[stale]

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[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue in 7 days. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please respond before the issue is closed, or open a new one after. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues

[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue in 7 days. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please respond before the issue is closed, or open a thread on the community forum. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues

[ale5000-git]

Hi, any change?

[BanzaiMan]

Hello, there.

You are using python-virtualenv from the official APT package repository, which hosts only one version of it at any point.

You could try changing the virtualenv versions on the fly with a different means, but I am afraid we are unlikely to provide you with support beyond that.

[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue in 7 days. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please respond before the issue is closed, or open a thread on the community forum. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues