Bump org.jetbrains.dokka from 1.9.10 to 1.9.20 (#561)

Bumps [org.jetbrains.dokka](https://github.com/Kotlin/dokka) from 1.9.10 to 1.9.20.
- [Release notes](https://github.com/Kotlin/dokka/releases)
- [Commits](Kotlin/dokka@v1.9.10...v1.9.20)

---
updated-dependencies:
- dependency-name: org.jetbrains.dokka
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version = "1.8.0" }
 protobuf = { id = "com.google.protobuf", version = "0.9.4" }
 test-retry = { id = "org.gradle.test-retry", version = "1.5.7" }
 publish-plugin = { id = "io.github.gradle-nexus.publish-plugin", version = "1.3.0" }
-dokka = { id = "org.jetbrains.dokka", version = "1.9.10" }
+dokka = { id = "org.jetbrains.dokka", version = "1.9.20" }
 qoomon-git-versioning = { id = "me.qoomon.git-versioning", version = "6.4.3" }
 kotlin-power-assert = { id = "com.bnorm.power.kotlin-power-assert", version = "0.13.0" }