First version should be 1. (#758)

Author: Nyholm

src/Plugin/composer.json

@@ -36,7 +36,7 @@
     "prefer": "dist",
     "extra": {
         "branch-alias": {
-            "dev-master": "4.0-dev"
+            "dev-master": "1.0-dev"
         }
     }
 }