Add release-update.sh script.

Script to run after a release has been tagged, signed and pushed
to git.  Will do a fresh checkout, verify the git tag, do fresh
build/dist, sign the dist with gpg, create a backup copy in HOME,
upload the tar.gz and sig to sourceware, checkout bzip2-htdocs,
copy over the new changes, manual, etc. and git push that to update
https://sourceware.org/bzip2/
1 file changed