[2.0] Workflow → Pipeline rename

[Jesse Glick]

Just a heads-up that in the context of 2.0 work, we are preparing a
rename of “Workflow” to “Pipeline” at the user/display level.

https://issues.jenkins-ci.org/browse/JENKINS-31153

gives some background on why this is important for new users.

Things like class names cannot and will not be changed. Currently
changing the plugin short name is also impossible.

[Kanstantsin Shautsou]

IMHO bad -> worse.