[android] do not try to package duplicate files in the publication

platform/android/gradle/gradle-bintray.gradle

@@ -47,7 +47,7 @@ publishing {
 bintray {
     user = mapboxBintrayUser
     key = mapboxBintrayApiKey
-    publications = ['MapboxMapsSdkPublication']
+    publications('MapboxMapsSdkPublication')
     pkg {
         repo = project.ext.mapboxBintrayRepoName
         name = project.ext.mapboxArtifactId
@@ -106,11 +106,6 @@ tasks.withType(Javadoc) {
     options.addStringOption('charset', 'UTF-8')
 }
 
-artifacts {
-    archives androidSourcesJar
-    archives androidJavadocsJar
-}
-
 afterEvaluate { project ->
     android.libraryVariants.all { variant ->
         tasks.androidJavadocs.doFirst {