For now, let's use dev-master.

Author: duncanmcclean

composer.json

@@ -45,7 +45,7 @@
         "pixelfear/composer-dist-plugin": "^0.1.5",
         "spatie/ignition": "^1.15",
         "spatie/invade": "^2.1",
-        "statamic/cms": "^6.0",
+        "statamic/cms": "dev-master",
         "stillat/proteus": "^4.0"
     },
     "require-dev": {
@@ -63,5 +63,5 @@
             "composer/package-versions-deprecated": true
         }
     },
-    "minimum-stability": "alpha"
+    "minimum-stability": "dev"
 }