Remove upper limit of twilio dependency. Way too instable.

Author: hannesvdvreken

composer.json

@@ -17,7 +17,7 @@
     "license": "MIT",
     "require": {
         "php": ">=5.5.0",
-        "twilio/sdk":"~3.12||~4.0"
+        "twilio/sdk":">=3.12.0"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^1.9",