Updated Slurm-GCP Terraform scripts and HPC Image

[Nick Ihli]

Slurm-GCP 4.0.3 is released! We've updated Slurm to its latest version - 20.11.7 - and are using Google Cloud's latest HPC image, which now supports hyperthreading. 

A NEWS file is provided to give more details on the changes. See the link below for information on other small changes.

https://github.com/SchedMD/slurm-gcp/blob/master/NEWS

The Marketplace listing is still using the previous HPC image, and we will be updating that soon.

Thanks,

Nick