Metall package: add v0.6 (#19854)
Metall package: add v0.6 (#19854)

* Metall: add version 0.2

* Add Metall v0.3

* Update Metall package to v0.4 and v0.5.

* Metall package: add v0.6
iulian787/spack,LLNL/spack,iulian787/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,LLNL/spack