Add conflicting puli versions

Author: sagikazarmark

composer.json

@@ -32,7 +32,11 @@
         "symfony/symfony": "^2.7|^3.0",
         "polishsymfonycommunity/symfony-mocker-container": "^1.0",
         "matthiasnoback/symfony-dependency-injection-test": "^0.7",
-        "puli/symfony-bundle": "^1.0@beta,>1.0.0-beta7"
+        "puli/symfony-bundle": "^1.0@beta"
+    },
+    "conflict": {
+        "puli/composer-plugin": "<1.0.0-beta9",
+        "puli/symfony-bundle": "<=1.0.0-beta7"
     },
     "suggest": {
         "puli/symfony-bundle": "Used for automatic service discovery"