bundle install parallelism issue (19.0.x)

[th-2021]

When I run the build on a system with a high core count bundle install fails.
Reducing it to 8 did help.

NCPUS=`nproc`
if (( NCPUS > 8 )); then
       NCPUS=8
fi

exec_as_git bundle install -j"${NCPUS}"