Add sourcesJar and javadocsJar to maven publish configuration. (#220)

Signed-off-by: Steven Shropshire <steven.shropshire@getbraintree.com>

Co-authored-by: Sarah Koop <skoop@paypal.com>

Author: sshropshire

Drop-In/build.gradle

@@ -98,11 +98,6 @@ task sourcesJar(type: Jar) {
     from android.sourceSets.main.java.srcDirs
 }
 
-artifacts {
-    archives javadocsJar
-    archives sourcesJar
-}
-
 signing {
     required {
         !version.endsWith("SNAPSHOT") && !version.endsWith("DEVELOPMENT")
@@ -124,6 +119,9 @@ afterEvaluate {
             release(MavenPublication) {
                 from components.release
 
+                artifact sourcesJar
+                artifact javadocsJar
+
                 groupId = 'com.braintreepayments.api'
                 artifactId = 'drop-in'
                 version = rootProject.versionName