Bump dokka-gradle-plugin from 1.4.20 to 1.4.30 (#39)

Bumps [dokka-gradle-plugin](https://github.com/Kotlin/dokka) from 1.4.20 to 1.4.30.
- [Release notes](https://github.com/Kotlin/dokka/releases)
- [Commits](Kotlin/dokka@v1.4.20...v1.4.30)

Signed-off-by: dependabot[bot] <support@github.com>

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

build.gradle

@@ -11,7 +11,7 @@ buildscript {
  dependencies {
  classpath 'com.android.tools.build:gradle:4.1.2'
  classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
- classpath 'org.jetbrains.dokka:dokka-gradle-plugin:1.4.20'
+ classpath 'org.jetbrains.dokka:dokka-gradle-plugin:1.4.30'
  }
 }