Execute some build environments using latest pytest and/or master

[nicoddemus]

As discussed in pytest-dev/pytest#2730

[goodboy]

It might be good to do both?

[nicoddemus]

Agreed, that's what I meant actually (updated the title).

[RonnyPfannschmidt]

i think we should have a cronjob for master/features of pytest and also have a cronjob for pytest to test with pluggy master

[nicoddemus]

Agreed. Could you please create a similar issue in pytest Ronny?