website: Add release_procedures.md

This documentation outlines the procedures carried out during a gem5
release.

Change-Id: I1933df257ab0ffd3454866977fdbdb32b72e8422
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/47440
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby R. Bruce <bbruce@ucdavis.edu>
2 files changed