UCX: add version 1.8.1 (#17972)
UCX: add version 1.8.1 (#17972)

Signed-off-by: Howard Pritchard <e96a0dc0e8681ea6cb2efe4a406fddb7f3896a73@lanl.gov>
iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,LLNL/spack,LLNL/spack,iulian787/spack,iulian787/spack,iulian787/spack,LLNL/spack