_ci_: Use goreleaser to build macos universal binaries (including M1 macs)

[ianconsolata]

This is a much needed change that creates a universal MacOS binary, including support for M1 based macs. We also automatically update the homebrew package repo to use the new universal binary.

I also used this opportunity to refactor the workflow slightly so we can test out goreleaser, a yaml based tool for building, packaging, and releasing go binaries on multiple platforms. It supports building binaries for to most of the platforms we care about, including Linux and MacOS, and also supports publishing those binaries automatically as releases in Github, Homebrew, Snap, and Apt.

If this trial goes well, I think we should eventually replace the entire release workflow with goreleaser. For now, this test is more tightly scoped to only change the MacOS release process, since that is the one we have the most issues with. This PR:
- Builds darwin-amd64 and darwin-arm64 binaries of lotus, lotus-miner,
and lotus-worker
- Packages them into a universal darwin binary
- Publishes those to a release in Github based on the current tag
- Uses the binaries in the release to auto-publish an updated homebrew
configuration to filecoin-project/homebrew-lotus
- Does a dry-run build to produce a snapshot on release branches
- Manually generate and upload checksums after goreleaser

I pushed a test tag on my private fork to ensure it works as expected, which generated a release and an update to homebrew:

• https://github.com/ianconsolata/lotus/releases/tag/v1.17.0-rc5,
• https://github.com/ianconsolata/homebrew-lotus

By running brew install ianconsolata/lotus/lotus you can try out the new MacOS installation process. It's been verified anecdotally on a few M1 macs, and my own non-M1 mac.

Checklist

Before you mark the PR ready for review, please make sure that:

• All commits have a clear commit message.
• The PR title is in the form of of <PR type>: <area>: <change being made>
  • example: fix: mempool: Introduce a cache for valid signatures
  • PR type: fix, feat, INTERFACE BREAKING CHANGE, CONSENSUS BREAKING, build, chore, ci, docs,perf, refactor, revert, style, test
  • area: api, chain, state, vm, data transfer, market, mempool, message, block production, multisig, networking, paychan, proving, sealing, wallet, deps
• This PR has tests for new functionality or change in behaviour
• If new user-facing features are introduced, clear usage guidelines and / or documentation updates should be included in https://lotus.filecoin.io or Discussion Tutorials.
• CI is green

[geoff-vball]

Merge this when you're ready :)