Revise Debbie Web Hook jobs (fix doc build)

[robe]

They changed the Generic Web Hook plugin to standardize on lowercase key names

​https://github.com/jenkinsci/generic-webhook-trigger-plugi/blob/master/CHANGELOG.md

1.30 (2018-03-08 17:59:01)
No issue

improve header variable name description

    Version 1.28 introduced RFC 2616 compatibility making all headers lowercase.
    This patch adds a note to make this fact more obvious.
    Example situation where this matters: a CI systems that checks for X-GitHub-Event header to make further decisions. Since 1.28 the resulting variable changes from X_GitHub_Event to x_github_event effectively breaking this process.

0fd81969349a1d0 jekader 2018-03-08 17:28:09
1.29 (2018-03-06 20:26:35)
GitHub #45 "This project is parameterized" parameters are being ignored if triggered bug

Keeping default values in parameterized jobs #45

602ea1fd613abd2 Tomas Bjerre 2018-03-06 20:25:41

I think the 1.28 change is what broke the doc building (as Dan Baston noticed) and the 1.30 will break the others, so have to change all of those that use regex to match by lower case.