client: make files an array (#46)

Author: Twey

client/package.json

@@ -4,7 +4,7 @@
     "description": "Web client for the Linera blockchain",
     "main": "dist/linera_web.js",
     "types": "dist/linera_web.d.ts",
-    "files": "dist",
+    "files": [ "dist" ],
     "type": "module",
     "scripts": {
         "install": "true",