bump library version to 2.2.0

Author: serggl

library/build.gradle

@@ -68,7 +68,7 @@ afterEvaluate {
 
                 groupId = 'com.anjlab.android.iab.v3'
                 artifactId = 'library'
-                version = '2.1.0'
+                version = '2.2.0'
 
                 pom {
                     name = 'Android In-App Billing v3 Library'