First of all, there are no suppliers: publishing in Lumen. You can check using php artisan list and it will show that it is missing the vendor command:

Available commands:
completion           Dump the shell completion script
help                 Display help for a command
list                 List commands
migrate              Run the database migrations
auth
 auth:clear-resets    Flush expired password reset tokens
cache
 cache:clear          Flush the application cache
....
schedule
 schedule:run         Run the scheduled commands
 schedule:work        Start the schedule worker
schema
 schema:dump          Dump the given database schema

You can use various solutions, such as:

• Just use Laravel

  This is the easiest and most reliable way to install Rakutentech/Laravel-request-docs. Lumen is a lightweight framework and it is to be expected that it lacks the features available in Laravel.

• Install another package

  You can search on packagist and find at least two alternatives. One has been sitting there for two years, mr-bug-miner/lumen -doc. The other one is davmixcool/lumen-apidoc-generator a> which has been sitting there for 4 years. Neither package looks promising - but you can always try it.

• Install compatibility package

  Regarding another question, someone asked why they can't release zizaco/entrust packge. Got the answer and the solution is to use irazasyed/larasupport. There are other alternatives, so take your pick.

• Add your own "compatibility" tips

  This is the most troublesome, I don’t agree with it. You can copy VendorPublishCommand.php into app/Console/Commands and see if it works. However, I believe you need to remove the original code a bit - specifically the VendorTagPublished event.

It will be easier for you if you have already started your research from the error message.

Also, a bit of advice, generally avoid requesting off-site resources. Please be careful whenever you ask for an alternative package.