build(okhttp): remove redundant plugins and repositories blocks

Author: buongarzoni

rollbar-okhttp/build.gradle.kts

@@ -1,13 +1,5 @@
-plugins {
-    id("java")
-}
-
 group = "com.rollbar.okhttp"
 
-repositories {
-    mavenCentral()
-}
-
 dependencies {
     testImplementation(platform("org.junit:junit-bom:5.14.3"))
     testImplementation("org.junit.jupiter:junit-jupiter")