Fix build files

Author: NaikSoftware

example-client/build.gradle

@@ -8,7 +8,6 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.3.0'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.5'
     }
 }
 

lib/build.gradle

@@ -8,7 +8,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.3.0'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.5'
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
         classpath 'org.codehaus.groovy:groovy-android-gradle-plugin:2.0.0'
     }
 }