announce-gen: add more info the auto-generated announce template
* build-aux/announce-gen (readable_interval, readable_interval0):
New functions.
(digest_file_base64_wrap): New function to add padding to the
base64-encoded SHA256 checksums.
(print_checksums): Use that wrapper. Indent each line by two spaces.
(main): Emit new sections, e.g., these lines from grep-3.8's release:
- There have been 104 commits by 6 people in the 55 weeks since 3.7.
- The following people contributed changes to this release: (and list)
I tested with this, running from a sibling cloned grep directory:
../gnulib/build-aux/announce-gen --release-type=stable \
--package-name=grep --previous-version=3.7 --current-version=3.8 \
--gpg-key-id=0x7FD9FCCB000BEEEE --url-directory=https://testing
Also, reference the cksum programs from coreutils-9.2 and from OpenBSD.