Host doesn't support nested folder structures for deployment. How do I adjust Composer? So, I have to deploy a drupal 8 site to a host which doesn't provide functionality to specify an entry point for a Drupal site which is nested below the site root folder. How can I update the folder structure to have everything in the server's site root?
What I tried initially was to move the contents of the site_root/web/ folder up to the site root, but this causes 500 errors. I'm not sure since I can't see the errors on the host server, but replicating the scenario on my dev machine points to the autoloader.php file looking in the wrong place PHP Fatal error:  require(): Failed opening required '/var/www/html/ab-test/../vendor/autoload.php'. 

I have tried to resolve this by first following the suggestion to re-run composer install from the site root but that doesn't seem to help. When I manually update where the autoloader.php should be looking, I then get this errorPHP Warning:  require(/var/www/html/ab-test/vendor/composer/../../load.environment.php) which again suggests that the file/folder structure is being set somewhere I'm not thinking of or don't have enough experience to check. 
So, my convoluted question comes down to how do I switch from a nested to a non-nested folder structure without everything freaking out?
As you are using an Apache server, you may try to set the Drupal root folder using an .htaccess file in your site_root:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.example.com$
RewriteCond %{REQUEST_URI} !web/
RewriteRule (.*) /web/$1 [L]


(Replace example.com with your actual domain name.)

This way, you can keep the "nested" folder structure created using Composer and serve all requests for your domain with the web sub folder.