Update Kotlin [1.3.31 -> 1.3.61] and dokka [0.10.0 -> 0.10.1].

Author: greenrobot-team

objectbox-kotlin/build.gradle

@@ -3,8 +3,8 @@ version= rootProject.version
 
 buildscript {
     ext.javadocDir = "$buildDir/docs/javadoc"
-    ext.kotlin_version = '1.3.31'
-    ext.dokka_version = '0.10.0'
+    ext.kotlin_version = '1.3.61'
+    ext.dokka_version = '0.10.1'
 
     repositories {
         mavenCentral()