- scripts/log2changes.pl was not included in release tarballs, which broke
reproducible builds
- since log2changes uses git to generate the contents, it makes it difficult
to generate the same contents later (it would need to be fixed)
- the CHANGES file has outlived its purpose. the main changes are in the
RELEASE-NOTES, the rest are better tracked directly using git or on GitHub
- put a fixed CHANGES.md in there instead pointing out where the info lives
now
Closes#14331
