feat: make --keep-going

This will ensure that as much as possible ends up in the buildcache.

containers/jug/dev.Dockerfile

@@ -107,7 +107,7 @@ RUN --mount=type=cache,target=/var/cache/spack-mirror,sharing=locked    \
     cd /opt/spack-environment                                           \
  && source $SPACK_ROOT/share/spack/setup-env.sh                         \
  && spack env activate --dir /opt/spack-environment/${ENV}              \
- && make --jobs ${jobs} --directory /opt/spack-environment              \
+ && make --jobs ${jobs} --keep-going --directory /opt/spack-environment \
     SPACK_ENV=${ENV}                                                    \
     BUILDCACHE_DIR=/var/cache/spack-mirror
 # FIXME disabled S3 buildcache until multipart upload fixed