update gradle to version gradle-5.1.1 and buildToolsVersion to 28.0.3

.travis.yml

@@ -4,8 +4,8 @@
 language: android
 android:
   components:
-    - build-tools-27.0.3
-    - android-27
+    - build-tools-28.0.3
+    - android-28
 script:
   - ./gradlew check jacoco assemble
   - bash <(curl -s https://codecov.io/bash)

build.gradle

@@ -6,7 +6,7 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.4.0'
         classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.8.0'
         classpath 'org.ajoberstar:gradle-git:1.7.2'
@@ -40,9 +40,8 @@ try {
 }
 
 project.ext.minSdkVersion = 16
-project.ext.compileSdkVersion = 27
-project.ext.buildToolsVersion = '27.0.3'
-project.ext.supportLibVersion = '27.1.1'
+project.ext.compileSdkVersion = 28
+project.ext.supportLibVersion = '28.0.0'
 
 task showVersion {
     doLast {

config/android-common.gradle

@@ -1,6 +1,5 @@
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
     defaultConfig {
         minSdkVersion rootProject.minSdkVersion
         targetSdkVersion rootProject.compileSdkVersion

config/javadoc.gradle

@@ -28,6 +28,6 @@ task javadocJar(type: Jar, dependsOn:androidJavadoc) {
 afterEvaluate {
     // fixes issue where javadoc can't find android symbols ref: http://stackoverflow.com/a/34572606
     androidJavadoc.classpath += files(android.libraryVariants.collect { variant ->
-        variant.javaCompile.classpath.files
+        variant.javaCompileProvider.get().classpath.files
     })
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Apr 06 13:27:13 PDT 2018
+#Thu May 02 16:24:22 CEST 2019
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip