- Disable spinner tests as the monkeypatch changed behaviour in pytest

- version update to 3.14.5
- Add ``--discover`` (fallback to ``TOX_DISCOVER`` environment variable via path separator) to inject python executables
to try as first step of a discovery - note the executable still needs to match the environment by :user:`gaborbernat`.
`#1526 `_
- Bump minimal six version needed to avoid using one incompatible with newer
virtualenv. - by :user:`ssbarnea`
`#1519 `_
- Avoid pypy test failure due to undefined printout var. - by :user:`ssbarnea`
`#1521 `_