fix: resolve Laravel home using __DIR__

[jaulz]

trafficstars

When using a mono repository, the Laravel folder is not the root folder. Hence, we cannot simply take the Lambda Root and expect Laravel files to be present. Instead, this PR uses the current directory of the script and just finds the Laravel files relatively via going up the directory tree.

[deleugpn]

I just opened https://github.com/brefphp/laravel-bridge/pull/131 as an alternative to this and explained why I preferred the previous approach.

[deleugpn]

#131 has been merged and should address this, so I'm going to close this one.

If the author, or anybody else, feels differently, please feel free to open an issue or another PR for us to discuss it further!