bump mock-client version

Author: dbu

composer.json

@@ -33,7 +33,7 @@
         "mockery/mockery": "~0.9.5",
         "monolog/monolog": "^1.0",
         "php-http/guzzle6-adapter": "^1.0 || ^2.0",
-        "php-http/mock-client": "^0.3.2",
+        "php-http/mock-client": "^1.2",
         "phpunit/phpunit": "^5.7 || ^6.0",
         "symfony/process": "^3.4 || ^4.0",
         "symfony/http-kernel": "^3.4 || ^4.0"