How to update/sync composer.json with entries from composer.lock

Question

I have following in my composer.json

{
  "require": {
       "vendor/package": "^2.0.0", // but installed 2.1.1 because of the ^
   }
}

how do I update/sync the composer.json from composer.lock to have the latest installed/exact version "vendor/package": "^2.1.1" I also have quite a few packages, updating it by hand is tedious.