Update package.json of next-js sample

Was causing install errors and by changing the version notation of next package, it worked.

Author: Amro Anwer

1.hello-world/7.read-video-nextjs/package.json

@@ -10,7 +10,7 @@
     },
     "dependencies": {
         "dynamsoft-javascript-barcode": "9.6.0",
-        "next": ">=12.1.0",
+        "next": "^12.1.0",
         "react": "17.0.2",
         "react-dom": "17.0.2"
     },