from one of the forum i found that i didn’t run the following command:
php /usr/bin/composer install --no-dev
When i run this command i am getting the following error 
Problem 1
- spatie/browsershot 3.41.0 requires php ^7.4|^8.0 → your PHP version (7.3.24) does not satisfy that requirement.
- spatie/browsershot 3.41.0 requires php ^7.4|^8.0 → your PHP version (7.3.24) does not satisfy that requirement.
- Installation request for spatie/browsershot 3.41.0 → satisfiable by spatie/browsershot[3.41.0].
The original guide from invoice ninja didn’t mention this step though. Not sure which guide i should follow for my installation now
https://forum2.invoiceninja.com/t/install-invoice-ninja-v5-on-ubuntu-20-04/4588
or