using npx, we can run all redocly commands without doing a global
install of redocly/cli (-g flag).

I also noticed we were using `latest` which outside of dev tests
is not recommended.

Some shorthand flags were also migrated to the long ones (--output).

when upstream updates swagger-cli to 4.0.5 this file needs to
be updated to remove the JonasGroeger/swagger-cli project.