Complete AndroidX migration

@shaxxxx Let me know if I missed something.

+## 0.1.3
+
+* Completed AndroidX migration.
+
 ## 0.1.2+8
 
 * Updated documentation.

@@ -8,7 +8,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.0'
     }
 }
 
@@ -26,7 +26,7 @@ android {
 
     defaultConfig {
         minSdkVersion 16
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
     lintOptions {
         disable 'InvalidPackage'

 org.gradle.jvmargs=-Xmx1536M
 
+android.useAndroidX=true
+android.enableJetifier=true

@@ -38,7 +38,7 @@ android {
         targetSdkVersion 28
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
     buildTypes {
@@ -56,6 +56,6 @@ flutter {
 
 dependencies {
     testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    androidTestImplementation 'androidx.test:runner:1.1.0'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
 }

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.0'
     }
 }
 

 org.gradle.jvmargs=-Xmx1536M
 
+android.useAndroidX=true
+android.enableJetifier=true

 name: wakelock
 description: This plugin allows you to keep Android and iOS devices awake, i.e. prevent the screen from sleeping by toggling the wakelock of the device on or off.
-version: 0.1.2+8
+version: 0.1.3
 author: creativecreatorormaybenot <19204050+creativecreatorormaybenot@users.noreply.github.com>
 homepage: https://github.com/creativecreatorormaybenot/wakelock