build-unit-test-docker: cereal: get upstream c++20 fixes
build-unit-test-docker: cereal: get upstream c++20 fixes

Signed-off-by: Patrick Williams <cbb7353e6d953ef360baf960c122346276c6e320@stwcx.xyz>
Change-Id: Iaa03418fdad4405f2f102c283bfaafcdad10c042

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts