android: including signing configuration

android/build.gradle

@@ -22,6 +22,7 @@ buildscript {
 
 apply plugin: "net.ltgt.errorprone"
 apply plugin: 'com.github.dcendents.android-maven'
+apply plugin: "signing"
 
 android {
     compileSdkVersion 27
@@ -51,6 +52,11 @@ dependencies {
     testImplementation 'com.google.truth:truth:0.39'
 }
 
+signing {
+    required false
+    sign configurations.archives
+}
+
 task javadocs(type: Javadoc) {
     source = android.sourceSets.main.java.srcDirs
     // TODO(ericgribkoff) Fix javadoc errors