build: Update bom to oldest included version

[NotMyFault]

(Possible) prerequisite for #2093 and newer changes, while retaining compatibility with the oldest bom profile.

Alternatively, integration tests could use a newer bom, but 2.289.x is a pretty conservative baseline.

[NotMyFault]

Javadoc errors have been fixed.

I don't know much about JCasC, but looking on the test results, it appears that JenkinsConfiguratorTest#shouldExportLabelAtoms()'s ExpectedLabelsConfiguration.yml expects something different than the test actually returns 🤔

[jetersen]

@NotMyFault I believe Jenkins core introduced new default labels?

[NotMyFault]

@NotMyFault I believe Jenkins core introduced new default labels?

Possibly? I'm not much familiar with all older changes from past year 👀

[codecov]

Codecov Report

Merging #2095 (5542c3d) into master (079e571) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #2095   +/-   ##
=========================================
  Coverage     81.01%   81.01%           
  Complexity      844      844           
=========================================
  Files            72       72           
  Lines          2507     2507           
  Branches        353      353           
=========================================
  Hits           2031     2031           
  Misses          365      365           
  Partials        111      111           

Impacted Files	Coverage Δ
.../io/jenkins/plugins/casc/SecretSourceResolver.java	100.00% <ø> (ø)
.../plugins/casc/impl/secrets/DockerSecretSource.java	66.66% <ø> (ø)

[NotMyFault]

Btw, why do builds run on GH actions and on ci.j?

[jetersen]

GH actions usually is faster and easier to navigate then ci.j. Also when ci.j has issues GH actions rarely has.

[jetersen]

#2097