Add a FreeBSD cross build to the cirrus alt build task

This just verifies that a non-cgo podman binary can build for FreeBSD.

[NO NEW TESTS NEEDED]

Signed-off-by: Doug Rabson <dfr@rabson.org>

.cirrus.yml

@@ -369,6 +369,8 @@ alt_build_task:
             ALT_NAME: 'Test build podman-next Copr RPM'
       - env:
             ALT_NAME: 'Alt Arch. Cross'
+      - env:
+            ALT_NAME: 'FreeBSD Cross'
     # This task cannot make use of the shared repo.tbz artifact.
     clone_script: *full_clone
     setup_script: *setup