Update Android gradle plugin

build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.0-alpha6'
+        classpath 'com.android.tools.build:gradle:3.0.0-alpha7'
         classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
         classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.6.4'
         classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'

uhabits-core/build.gradle

@@ -17,7 +17,6 @@ dependencies {
     implementation 'com.android.support:support-annotations:25.3.1'
     implementation 'com.google.code.findbugs:jsr305:3.0.2'
     implementation 'org.apache.commons:commons-lang3:3.5'
-    implementation 'org.apache.commons:commons-io:1.3.2'
     implementation 'com.google.code.gson:gson:2.7'
 
     testImplementation 'junit:junit:4+'