Upgrade twilio-java 7.x version

Author: hortega

tools/snippet-testing/model/dependency.rb

@@ -22,7 +22,7 @@ class Dependency
       RUBY_NAME   => ['4.13.0', '5.0.0.rc23'],
       NODE_NAME   => ['2.11.0', '3.3.0-alpha-1'],
       JAVA6_NAME  => {group: "com.twilio.sdk", name: 'twilio-java-sdk', version: '6.3.0', suffix: '-jar-with-dependencies'},
-      JAVA7_NAME  => {group: "com.twilio.sdk", name: 'twilio', version: '7.11.0-alpha-1', suffix: '-jar-with-dependencies'}
+      JAVA7_NAME  => {group: "com.twilio.sdk", name: 'twilio', version: '7.12.0-alpha-1', suffix: '-jar-with-dependencies'}
     }.freeze
 
     JAVA_DEPENDENCIES = {