resources: Update v20 URLs to v20-1

Change-Id: Ib1e91277361df3b67a4b37e3ae97244f679745b0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-resources/+/35438
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby R. Bruce <bbruce@ucdavis.edu>
7 files changed
tree: d57337f92b6d525922a7ab4158d9402369e228c2
  1. README.md
  2. src/