Updated README.md for Diktat 2.0

[nulls]

What's done:

• updated section about CLI
• updated sections for plugins

It closes #1793

[codecov[bot]]

Codecov Report

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

Comparison is base (b8062d8) 78.32% compared to head (a80f2ab) 78.32%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1839 +/- ## ========================================= Coverage 78.32% 78.32% Complexity 2458 2458 ========================================= Files 134 134 Lines 8696 8696 Branches 2201 2201 ========================================= Hits 6811 6811 Misses 906 906 Partials 979 979 ```

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[github-actions[bot]]

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

   166 files  ±0     166 suites  ±0   7m 6s :stopwatch: -29s 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 2a0b7221. ± Comparison against base commit 1b4b6c77.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

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

   166 files  ±0     166 suites  ±0   11m 53s :stopwatch: + 4m 44s 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 2a0b7221. ± Comparison against base commit 1b4b6c77.

:recycle: This comment has been updated with latest results.

[orchestr7]

do not merge until release done

[orchestr7]

@nulls merge?

[nulls]

@nulls merge?

No, 2.0 is not yet available on maven central