ci: add goreleaser to supercronic

[kidager]

Description

This PR adds GoReleaser to the CI which gives the ability to:

• build docker images for multiple architectures now
• push docker images to ghcr.io (But you can change/expand it to push to dockerhub or any other registry)
• easily expand to other platforms and architectures

You can see an example of the:

• Release: https://github.com/kidager/supercronic/releases/tag/v0.0.1-testing-007
• Docker image: https://github.com/kidager/supercronic/pkgs/container/supercronic/311816524?tag=0.0.1-testing-007

Related issues

This addresses #148
And is a start to solving #139 & #85 (You only need to add your dockerhub credentials as a secret, and some configuration to the .goreleaser.yaml

[tetienne]

You can link the go.mod instead: https://github.com/actions/setup-go#getting-go-version-from-the-gomod-file