support `bun.lock` as package manager lockfile

[RiskyMH]

Bun added support for a new lockfile format called bun.lock (it will soon be default, but bun.lockb will be supported for awhile) https://bun.sh/blog/bun-lock-text-lockfile

_{related #10}

[juliolmuller]

Beautiful! This is the only thing missing for my CLI tool to work perfectly!

[shellscape]

Folks, @antfu has released https://www.npmjs.com/package/package-manager-detector and it's a far better alternative. egoist is MIA these days.