Use ppm 2.0

Author: andig

composer.json

@@ -2,7 +2,7 @@
     "name": "php-pm/httpkernel-adapter",
     "license": "MIT",
     "require": {
-        "php-pm/php-pm": "^1.0|^2.0",
+        "php-pm/php-pm": "^2.0",
         "symfony/http-foundation": "^2.6|^3.0|^4",
         "symfony/http-kernel": "^2.6|^3.0|^4",
         "ringcentral/psr7": "^1.2"