Added php-pm/php-pm as required package

Author: marcj

composer.json

@@ -2,7 +2,8 @@
     "name": "php-pm/httpkernel-adapter",
     "require": {
         "symfony/http-foundation": "^2.6|^3.0",
-        "symfony/http-kernel": "^2.6|^3.0"
+        "symfony/http-kernel": "^2.6|^3.0",
+        "php-pm/php-pm": "dev-master"
     },
     "autoload": {
         "psr-4": {