The number of commit characters in patch files fetched from GitHub can change,
so we should use `full_index=1` to enforce full commit hashes (and a stable
patch `sha256`).
Similarly, URLs for branches like `master` don't give us stable patch files,
because branches are moving targets. Use specific tags or commits for those.
- [x] update all github patch URLs to use `full_index=1`
- [x] don't use `master` or other branches for patches
- [x] add an audit check and a test for `?full_index=1`
Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>
5df10c04cd