Automatic yarn updates as a post-checkout hook

package.json

{
  "devDependencies": {
    "ghooks": "^1.3.2"
  },
  "config": {
    "ghooks": {
      "post-checkout": "./script/yarn-update.hook.sh $2 $3"
    }
  }
}

yarn-update.hook.sh

#!/bin/bash

if [ "$1" != "$2" ]; then
    diff=$(git diff $1 $2 yarn.lock)
    if [ "$diff" != "" ]; then
        echo "yarn.lock has been changed! Installing dependencies..."
        yarn
    fi
fi