fix(deps): update dependency org.jetbrains.dokka:dokka-gradle-plugin to v1.9.20

Author: figure-renovate[bot]

buildSrc/build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 val gradleNexusVersion = "1.3.0"
 val kotlinVersion = "1.9.0"
 val ktLintVersion = "11.6.1"
-val dokkaVersion = "1.8.20"
+val dokkaVersion = "1.9.20"
 
 repositories {
     gradlePluginPortal()