Remove jcenter as it is ending

Author: ligi

build.gradle

@@ -31,7 +31,8 @@ buildscript {
     }
 
     repositories {
-        jcenter()
+        gradlePluginPortal()
+	mavenCentral()
     }
 
     dependencies {

lib/build.gradle

@@ -2,7 +2,7 @@ apply plugin: "kotlin"
 apply plugin: 'maven'
 
 repositories {
-    jcenter()
+    mavenCentral()
     maven { url 'https://jitpack.io' }
 }