Fixed bad caching defaults

Author: GrahamCampbell

composer.json

@@ -24,7 +24,7 @@
         "php-http/discovery": "^1.0",
         "php-http/client-implementation": "^1.0",
         "php-http/client-common": "^1.1",
-        "php-http/cache-plugin": "^1.1"
+        "php-http/cache-plugin": "^1.2"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.0",