fix: Update Dockerfile

[irvinlim]

Realized that the Dockerfile is still using go1.17, which can cause problems when attempting to use Go features in later versions.

• Update Dockerfile to use go1.23.
• Remove GOOS and GOARCH from the go build command, and allow the Go compiler to automatically detect this inside of docker buildx.
  • However, the current v0.5.0 images seem to still work on my M1 Macbook, so I'm not sure if this is even necessary.
• Remove unused hack/push-docker.sh, and prefer to use GH Actions for this workflow.
• Allow nightly push to the Git hash for snapshot purposes.