错误提示:laravel/horizon v1.4.3 requires ext-pcntl * -> the requested PHP extension pcntl is missing from your system
解决办法：
在 composer.json 中增加
“config”: {
“preferred-install”: “dist”,
“sort-packages”: true,
“optimize-autoloader”: true,
“platform”: {
“ext-pcntl”: “7.2”,
“ext-posix”: “7.2”
}
},