Update ssr-caching example (vercel#4363)

* Remove unnecessary dir key from next's argument
* Add license section to package.json

Author: yhirano55

examples/ssr-caching/package.json

@@ -12,5 +12,6 @@
     "next": "latest",
     "react": "^16.0.0",
     "react-dom": "^16.0.0"
-  }
+  },
+  "license": "ISC"
 }

examples/ssr-caching/server.js

@@ -4,7 +4,7 @@ const LRUCache = require('lru-cache')
 
 const port = parseInt(process.env.PORT, 10) || 3000
 const dev = process.env.NODE_ENV !== 'production'
-const app = next({ dir: '.', dev })
+const app = next({ dev })
 const handle = app.getRequestHandler()
 
 // This is where we cache our rendered HTML pages