Bump org.jetbrains.dokka from 1.8.10 to 1.8.20 (#517)

Bumps [org.jetbrains.dokka](https://github.com/Kotlin/dokka) from 1.8.10 to 1.8.20.
- [Release notes](https://github.com/Kotlin/dokka/releases)
- [Commits](Kotlin/dokka@v1.8.10...v1.8.20)

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

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

build.gradle.kts

@@ -4,7 +4,7 @@ import java.net.URL
 plugins {
  buildsrc.conventions.`kotlin-jvm`
  buildsrc.conventions.`maven-publish`
- id("org.jetbrains.dokka") version "1.8.10"
+ id("org.jetbrains.dokka") version "1.8.20"
  id("com.github.ben-manes.versions") version "0.46.0"
  kotlin("plugin.serialization")