java 21 compatibility and minor version iteration

[denis-yuen]

Description
Noticed CLI nightly builds have been failing since August 10th, investigating.
Added Java 21 compatibility (this is different from #293 in that this branch only allows us to work with Java 21 locally whereas that branch does the actual testing on Java 21 in a newer machine image)

Also iterated the minor version. Noticed that some nightly regression tests were failing, expecting older versions of cwltool.
Think that our client was testing itself as a 15.0-SNAPSHOT and thus getting the wrong requirements file after dockstore/dockstore#5958

Review Instructions
Wait a day and see if nightly build passes

Issue
n/a

Security
If there are any concerns that require extra attention from the security team, highlight them here.

Please make sure that you've checked the following before submitting your pull request. Thanks!

• Check that you pass the basic style checks and unit tests by running ./mvnw clean install
• If this PR is for a user-facing feature, create and link a documentation ticket for this feature (usually in the same milestone as the linked issue). Style points if you create a documentation PR directly and link that instead.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.99%. Comparing base (af86492) to head (05b8610).
Report is 3 commits behind head on develop.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop     #296      +/-   ##
=============================================
- Coverage      70.09%   69.99%   -0.10%     
  Complexity      1059     1059              
=============================================
  Files             47       47              
  Lines           6069     6069              
  Branches         801      801              
=============================================
- Hits            4254     4248       -6     
- Misses          1470     1475       +5     
- Partials         345      346       +1     

Flag	Coverage Δ
bitbuckettests	9.83% <ø> (ø)
confidentialtooltests	55.52% <ø> (-0.19%)	⬇️
confidentialworkflowtests	30.18% <ø> (-0.07%)	⬇️
nonconfidentialtests	32.27% <ø> (-0.14%)	⬇️
singularitytests	16.59% <ø> (ø)
unittests	8.35% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud