Fix the build tools in travis-ci

.travis.yml

@@ -27,6 +27,7 @@ android:
     components:
         - tools
         - build-tools-27.0.0
+        - build-tools-26.0.2
         - extra-android-m2repository
         - extra-google-m2repository
 

build.gradle

@@ -17,6 +17,7 @@ buildscript {
         google()
         jcenter()
     }
+
     dependencies {
         classpath 'com.android.tools.build:gradle:3.0.1'
         classpath 'com.google.gms:google-services:3.1.1'

mobile/build.gradle

@@ -32,8 +32,8 @@ android {
         applicationId "com.github.shadowsocks"
         minSdkVersion rootProject.minSdkVersion
         targetSdkVersion rootProject.sdkVersion
-        versionCode 196
-        versionName "4.3.0"
+        versionCode 200
+        versionName "4.4.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
         vectorDrawables.useSupportLibrary true
     }