Bump kotlin-gradle-plugin from 1.6.10 to 1.6.20

Bumps [kotlin-gradle-plugin](https://github.com/JetBrains/kotlin) from 1.6.10 to 1.6.20.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.6.20/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.6.10...v1.6.20)

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

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

quicktype-plugin/build.gradle

@@ -9,7 +9,7 @@ apply plugin: "com.gradle.plugin-publish"
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-reflect"
     implementation "com.github.node-gradle:gradle-node-plugin:3.2.1"
-    implementation "org.jetbrains.kotlin:kotlin-gradle-plugin:1.6.10"
+    implementation "org.jetbrains.kotlin:kotlin-gradle-plugin:1.6.20"
 
     testImplementation project(":test-common")
     testImplementation "org.jetbrains.kotlin:kotlin-test"