[QA] Coordinating update of CloudBees "Selenium" template

[Jeff Hall]

We recently made a change to the mediawiki_selenium Rubygem to re-name 
the BROWSER_LABEL environment variable to BROWSER[1].

In order for this change to work as expected with browser tests run via 
CloudBees, we'll need to update the "Selenium" template configuration[2] 
in CloudBees to use the same env variable name.

However, if we change the CloudBees template right now, that change will 
break browser tests in Gerrit repos that have not yet been updated to 
use version 0.2.6 of the mediawiki_selenium Rubygem.  The VisualEditor 
repo has been updated to use the latest version of the Rubygem, and thus 
the VE browser tests are currently failing because the old env variable 
name (BROWSER_LABEL) is still being exported by the "Selenium" template.

Long story short, I think we need to update all repos that have browser 
tests to use the version 0.2.6 Rubygem, and then update the CloudBees 
template once all of the repos are ready-to-go.

I'm not sure how to best coordinate such a universal change to all WMF 
repos that have browser tests - can anyone suggest the best way to 
proceed that will minimize disruption?

Thanks much,

Jeff


[1] https://gerrit.wikimedia.org/r/#/c/113354/
[2] 
https://wmf.ci.cloudbees.com/template/b3ec9061-3760-428c-b4b3-7dd49a7b08a9/configure