Does that help Uploading is enough. It's very popular approach - to have a separate build server, where the project is being built as a first stage of a building process, and then this already built project is uploaded on a production server.
composer rest server fails to start after upgrade to composer 0.19.6
Any of those help Its because of composer auto generated files not linking your folder or class (ramsey) . So, as i understand you can not run composer update or composer install on shared hosting, you should upload whole updated vendor folder to your server.
Install CakePHP on OS X w/ Composer Fails, lib-icu ^62.1 has the wrong version installed
I wish this help you i've had a similar problem with intl, icu, composer and cake. it's not simple but i think i could help you with some information. First, I think you have composer ponting to native php, not that one installed with homebrew, because of that you still getting this wrong version of icu.
If Composer cannot be installed on production server is it OK to track vendor folder in Git?