Use diktat-runner:shadow as variant

[nulls]

What's done:

• shadow jar as variant is due to Gradle multiply artifacts issue

[codecov[bot]]

Codecov Report

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

Comparison is base (e51bcf6) 78.33% compared to head (a59f6f3) 78.32%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1875 +/- ## ============================================ - Coverage 78.33% 78.32% -0.02% Complexity 2458 2458 ============================================ Files 134 134 Lines 8696 8696 Branches 2201 2201 ============================================ - Hits 6812 6811 -1 - Misses 905 906 +1 Partials 979 979 ```

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[github-actions[bot]]

JUnit Tests (macOS, EnricoMi/publish-unit-test-result-action@v2)

   166 files  ±0     166 suites  ±0   6m 15s :stopwatch: + 2m 7s 1 426 tests ±0  1 388 :heavy_check_mark: ±0  38 :zzz: ±0  0 :x: ±0  2 805 runs  ±0  2 767 :heavy_check_mark: ±0  38 :zzz: ±0  0 :x: ±0 

Results for commit c9d56b0b. ± Comparison against base commit e51bcf6c.

[github-actions[bot]]

JUnit Tests (Windows, EnricoMi/publish-unit-test-result-action@v2)

   166 files  ±0     166 suites  ±0   7m 29s :stopwatch: -3s 1 426 tests ±0  1 409 :heavy_check_mark: ±0  17 :zzz: ±0  0 :x: ±0  2 805 runs  ±0  2 788 :heavy_check_mark: ±0  17 :zzz: ±0  0 :x: ±0 

Results for commit c9d56b0b. ± Comparison against base commit e51bcf6c.