all: add homebrew config to goreleaser

This commit adds a `brews` stanza to the goreleaser config, creating and updating a homebrew tap for the `cue` binary distribution.

Note: This assumes that `https://github.com/cuelang/homebrew-tap` exists and can be pushed to from the CI tooling. The mechanics of that integration are a bit unclear in the `goreleaser` docs.

One potential addition:
```
  commit_author:
    name: cuebot
    email: gitbot@cuelang.org
```
Or something similar to this.

I tried to test this locally, but was unable to...

Closes #55
https://github.com/cuelang/cue/pull/55

GitOrigin-RevId: aaa4ddc5996eaae2999b20a3cf191616d03dc013
Change-Id: I6388650cea0d1d523f1ec8c02d833d79e28d4ac6
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2380
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/.goreleaser.yml b/.goreleaser.yml
index 8115f3c..cff0c42 100644
--- a/.goreleaser.yml
+++ b/.goreleaser.yml
@@ -54,3 +54,12 @@
   filters:
     exclude:
     - '^test:'
+
+brews:
+- github:
+    owner: cuelang 
+    name: homebrew-tap
+  homepage: "https://github.com/cuelang/cue"
+  description: "CUE is an open source data constraint language which aims to simplify tasks involving defining and using data."
+  test: |
+    system "#{bin}/cue version"