Bump to v3.9.0 (#245)

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## What
Bump minor version 

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## Test Plan
N/A

## Demo
N/A

## How

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Merge this once we merge in the `showKeyboard()` PR

README.md

@@ -1,4 +1,4 @@
-# Forage Android SDK (`v3.8.1`)
+# Forage Android SDK (`v3.9.0`)
 
 You can use the Forage Android SDK to process online-only and/or Terminal POS EBT payments. The SDK provides UI components known as Forage Elements and associated methods that perform payment operations.
 

forage-android/build.gradle

@@ -10,7 +10,7 @@ apply plugin: ShadowAarDependenciesPlugin
 
 ext {
     PUBLISH_GROUP_ID = 'com.joinforage'
-    PUBLISH_VERSION = '3.8.1'
+    PUBLISH_VERSION = '3.9.0'
     PUBLISH_ARTIFACT_ID = 'forage-android'
     PUBLISH_DESCRIPTION = 'Forage Android SDK'
     PUBLISH_URL = 'https://github.com/teamforage/forage-android-sdk'