Use selenium-webdriver gem 3.141.0+

What does this MR do?

gem 'selenium-webdriver', '~> 3.141'

also pulled minor versions past 141, i.e., also fetched 142.3. let's lock down to 141.

Reason: It's possible that an update from 3.142.2 started breaking things. that could explain the "out of the blue" failures. 3.142.2 was released May 11th 2019. we started seeing the failures around May 12th.

~> 3.141 pulled these 3.142 versions

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content