fix(package): Only support current boardgame.io

Future boardgame.io versions (likely >=0.42) will drop support for 
certain renamed database methods. This change indicates that this 
release will cease to work with a future boardgame.io version.

package.json

@@ -75,6 +75,6 @@
     "firebase-admin": "^9.0.0"
   },
   "peerDependencies": {
-    "boardgame.io": ">=0.40.0"
+    "boardgame.io": ">=0.40 <0.42"
   }
 }