Bump Plugin Utilities API from 2.14.0 to 2.16.0

[basil]

Adapting to jenkinsci/plugin-util-api-plugin#161. The motivation for this is getting jenkinsci/bom up and running with JENKINS-45047, which exposes this compatibility problem.

Monkey see, monkey do style programming (copying warnings-ng), so please don't be too hard on me. I have no idea what I am doing here, just banging around on a keyboard until the tests pass. If something doesn't make sense to you, there is probably a better way. One thing I am confident about is that each and every change in this PR is necessary to get the tests to pass, so if you think some change isn't necessary, try testing without it and see what happens.

CC @timja @uhafner

[codecov]

Codecov Report

Merging #164 (8e06a04) into master (a3bde2f) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #164   +/-   ##
=========================================
  Coverage     85.38%   85.38%           
  Complexity      152      152           
=========================================
  Files            17       17           
  Lines           746      746           
  Branches         57       57           
=========================================
  Hits            637      637           
  Misses           89       89           
  Partials         20       20           

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[basil]

Please hold as I fix the style checks that were reported to me when doing a CI build but not reported to me in a local build. =\

[basil]

Checkstyle now complains about redundant public modifiers on lines 164 and 175 of WithChecksStepITest, but I couldn't figure out how to remove the public modifiers without breaking either compilation or @TestExtension. I ran into a similar problem in core and ended up suppressing the violations in cases like this. Could the maintainers please suppress these warnings? Thanks!

[timja]

FWIW I’ve hit this before :( #99

[basil]

The build is now green.