Initial shmem4py release with support for:
* [Cray OpenSHMEMX](https://cray-openshmemx.readthedocs.io/)
* [Open Source Software Solutions (OSSS) OpenSHMEM](https://github.com/openshmem-org/osss-ucx)
* [Open MPI OpenSHMEM](https://www.open-mpi.org/doc/v3.1/man3/OpenSHMEM.3.php)
* [OSHMPI](https://pmodels.github.io/oshmpi-www/)
* [Sandia OpenSHMEM](https://github.com/Sandia-OpenSHMEM/SOS)