feat: goreleaser setup

[caarlos0]

closes #9
closes #8

This adds:

• build the binaries for windows, linux and darwin, amd64, arm64 and 386 (can add more if you want/need)
• keyless sign archives with cosign
• create a release on github and upload the artifacts
• create/update the formula on a homebrew-tap repository

TODOs for @orlangure

• create a homebrew-tap repository
• create a personal access token with write access
• add it as a secret to this project (named GITHUB_PAT)
• cut a new tag

[orlangure]

This is so cool! It's been a while since I wanted to use goreleaser, and finally there is a reason.

I only had to change the secret name (github won't allow to start secrets with GITHUB_), so I'm pushing another commit and merging this 😼

Thank you!