Fix branch alias after PR retarget [skip CI]

Jean85 · Jean85 · commit b77d484d6bac · 2018-10-31T12:45:50.000+01:00
diff --git a/composer.json b/composer.json
@@ -37,7 +37,8 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.0-dev"
+            "2.x": "2.x-dev",
+            "dev-master": "1.8-dev"
         }
     }
 }
