Should we use latest pip?

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I see the following warning running pip install:

You are using pip version 8.1.1, however version 10.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

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We could upgrade pip during provisioning...

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We should check how it works now that we use pyenv.

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Related to https://github.com/coopdevs/odoo-role/blob/master/defaults/main.yml#L7