Update github build actions to use Java 21

[JPercival]

• Build with Java 21
• Update github actions version.

[github-actions[bot]]

Formatting check succeeded!

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (3af4cbf) 42.62% compared to head (ae65d35) 42.62%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #387 +/- ## ========================================= Coverage 42.62% 42.62% Complexity 1585 1585 ========================================= Files 223 223 Lines 11708 11708 Branches 1633 1633 ========================================= Hits 4990 4990 Misses 6108 6108 Partials 610 610 ```

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