Fix missing deployment jobs for Git v2.28
While the test jobs for Git v2.28 were added already in 3e75b17a (Upgrade to Git v2.28.0.rc1, 2020-07-20), the commit forgot to add deployment jobs to the build matrix.
Fix this by adding two new deployment jobs for Git v2.28.
@zj-gitlab Didn't see one had to add jobs for deployment, too.