fix: update dev-master to 2.0.x-dev, not 3.0.x-dev

I'd misread the original by-laws around typehint addition to require two new major versions, when it's just a minor version and a major version.

Author: weierophinney

composer.json

@@ -21,7 +21,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "3.0.x-dev"
+            "dev-master": "2.0.x-dev"
         }
     }
 }