Migrate cross-compile task to github-actions

As of Sept. 1st 2023 Cirrus-CI will start charging for hosted compute
time.  At the time of this commit, according to the containers-org
billing page, github provides 133 "free" minutes per month of MacOS
time.  However, the same page shows 0 minutes used across-the-board, so
perhaps they're not counting minutes at all.

**Note**: While it's possible to synchronize job execution with
Cirrus-CI, in practice it's difficult to do.  There may be unintended
consequences due to the final CI-state not being joined in any way. Also,
this new workflow will execute on all branches and all PRs w/o regard to
the PR title (Cirrus-CI was sensitive to several key-words).

Signed-off-by: Chris Evich <cevich@redhat.com>

.cirrus.yml

@@ -132,29 +132,6 @@ vendor_task:
         - './hack/tree_status.sh'
 
 
-# Confirm cross-compile ALL architectures on a Mac OS-X VM.
-cross_build_task:
-    name: "Cross Compile"
-    alias: cross_build
-    only_if: >-
-        $CIRRUS_CHANGE_TITLE !=~ '.*CI:DOCS.*' &&
-        $CIRRUS_CRON != 'multiarch'
-
-    osx_instance:
-        image: ghcr.io/cirruslabs/macos-ventura-base:latest
-
-    script:
-        - brew update
-        - brew install go
-        - brew install go-md2man
-        - brew install gpgme
-        - go version
-        - make cross CGO_ENABLED=0
-
-    binary_artifacts:
-        path: ./bin/*
-
-
 unit_task:
     name: 'Unit tests w/ $STORAGE_DRIVER'
     alias: unit
@@ -381,7 +358,6 @@ success_task:
       - unit
       - conformance
       - vendor
-      - cross_build
       - integration
       - in_podman
       - image_build

.github/workflows/test_macos_build.yml

@@ -0,0 +1,22 @@
+---
+
+name: Test MacOS Build
+
+on: [push, pull_request]
+
+jobs:
+  test_macos_build:
+    name: Test MacOS Build
+    runs-on: macos-latest
+    steps:
+      - run: |
+          brew update
+          brew install go
+          brew install go-md2man
+          brew install gpgme
+          go version
+          make cross CGO_ENABLED=0
+      - uses: actions/upload-artifact@v3
+        with:
+          name: binary
+          path: "./bin/*"