Fix bsb-core `parallel` variant

The parallel variant is not selected, because depends_on("py-tblib@1.7.0:") (for py-mpipool) can't be satisfied.

mentioned in merge request !618 (merged)

added 7 commits

• 55d55f35...5401c483 - 5 commits from branch spack_v0.23.0
• 8536f9ca - feat(py-tblib): copy package from upstream
• fdc801c0 - feat(py-tblib): add version 2.0.0

Compare with previous version

added 2 commits

• 401fdb2e - feat(py-tblib): copy package from upstream
• a7f5aaf7 - feat(py-tblib): add version 2.0.0

Compare with previous version

merged