Upgrade to Font Awesome 5.3.1, bump version

CHANGELOG.md

+## 8.1.0
+
+  * Upgrade to Font Awesome Icons 5.3.1
+
 ## 8.0.1
 
   * Fix documentation

example/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.1.2'
     }
 }
 

pubspec.yaml

@@ -2,7 +2,7 @@ name: font_awesome_flutter
 description: The Font Awesome Icon pack available as Flutter Icons
 author: Brian Egan <brian@brianegan.com>
 homepage: https://github.com/brianegan/font_awesome_flutter
-version: 9.0.0
+version: 8.1.0
 
 environment:
   sdk: ">=2.0.0-dev.28.0 <3.0.0"