DOC: clipboard library missing in doc env on travis

[jorisvandenbossche]

The doc builds sees the following failure:

PyperclipException: 
    Pyperclip could not find a copy/paste mechanism for your system.
    For more information, please visit https://pyperclip.readthedocs.org 

which is happening since the refactor of the CI envs in #24632. In unifying things we might have by accident removed some clipboard related things for the doc build.

cc @saurav2608 if you want to take a look at this, always welcome

[jorisvandenbossche]

Going through the diff of that PR, I actually don't notice anything related to clipboard (no occurrence of xclip or xsel, ..)

But according to the travis logs, it is still that commits that started to fail (of course can also be something unrelated to the diff, but I don't directly see any change in library versions), https://travis-ci.org/pandas-dev/pandas/jobs/515983449 vs https://travis-ci.org/pandas-dev/pandas/jobs/515983803

[saurav2608]

Definitely introduced post #24632 . I will investigate and confirm.

[jorisvandenbossche]

Thanks for taking a look!

[jorisvandenbossche]

@jreback this can stay on the 0.25 milestone. Currently we show an error in the docs. Last resort, we just convert it to a plain code block before the release, to at least show the expected behaviour.

[jreback]

sure np