BREAKING CHANGE: update scala version to 3, support for scala 2.13+ will be dropped.

[andrewrigas]

Closes #64

[codecov[bot]]

Codecov Report

Attention: 33 lines in your changes are missing coverage. Please review.

Comparison is base (abcfae1) 89.92% compared to head (9058caf) 64.31%.

:exclamation: Current head 9058caf differs from pull request most recent head 0b98bf9. Consider uploading reports for the commit 0b98bf9 to get more accurate results

Files	Patch %	Lines
...s/oath-core/src/main/scala/io/oath/JwtIssuer.scala	57.14%	6 Missing :warning:
...rc/main/scala/io/oath/config/JwtIssuerConfig.scala	50.00%	6 Missing :warning:
...th-core/src/main/scala/io/oath/config/config.scala	37.50%	5 Missing :warning:
...oath-core/src/main/scala/io/oath/JwtVerifier.scala	0.00%	4 Missing :warning:
...src/main/scala/io/oath/jsoniter_scala/syntax.scala	55.55%	4 Missing :warning:
...th-circe/src/main/scala/io/oath/circe/syntax.scala	76.92%	3 Missing :warning:
.../main/scala/io/oath/config/JwtVerifierConfig.scala	77.77%	2 Missing :warning:
...src/main/scala/io/oath/utils/DecryptionUtils.scala	50.00%	1 Missing :warning:
...src/main/scala/io/oath/utils/EncryptionUtils.scala	50.00%	1 Missing :warning:
...th-core/src/main/scala/io/oath/utils/package.scala	90.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #127 +/- ## =========================================== - Coverage 89.92% 64.31% -25.61% =========================================== Files 24 21 -3 Lines 377 468 +91 Branches 24 2 -22 =========================================== - Hits 339 301 -38 - Misses 38 167 +129 ```

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