* feat: add multiarch docker build support
adds docker build support for the following platforms:
- amd64 (default)
- arm64v8
- armv6
- armv7
also adds GOOS and GOARCH information to the buildString
utilizes docker manifest to store image architecture metadata
* chore: update goreleaser action to v4
* chore: update docker login action to v2
* chore: format buildstring
with the new recent changes in dockerhub[1] we should
start pushing images to ghcr, and eventually phase out
the existing dockerhub setup.
[1]: https://blog.alexellis.io/docker-is-deleting-open-source-images/
Signed-off-by: Chinmay D. Pai <chinmay.pai@zerodha.com>