support eslint plugin 6.*

[mr-feek]

right now this project depends on eslint plugin ^5.37.0.

When I try to install the likes of https://github.com/sweepline/eslint-plugin-unused-imports , I get

npm install eslint-plugin-unused-imports --save-dev
npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR!
npm ERR! While resolving: [email protected]
npm ERR! Found: @typescript-eslint/[email protected]
npm ERR! node_modules/@typescript-eslint/eslint-plugin
npm ERR!   @typescript-eslint/eslint-plugin@"^5.37.0" from [email protected]
npm ERR!   node_modules/eslint-plugin-adonis
npm ERR!     dev eslint-plugin-adonis@"^2.1.1" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! dev eslint-plugin-unused-imports@"*" from the root project
npm ERR!
npm ERR! Conflicting peer dependency: @typescript-eslint/[email protected]
npm ERR! node_modules/@typescript-eslint/eslint-plugin
npm ERR!   peerOptional @typescript-eslint/eslint-plugin@"^6.0.0" from [email protected]
npm ERR!   node_modules/eslint-plugin-unused-imports
npm ERR!     dev eslint-plugin-unused-imports@"*" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.