Git history is not for everyone. Let's introduce a user-oriented change
log. Ideally, this file should be updated incrementally when adding
a new feature. I have added contributors guidelines in README.md.
Update release.sh to automatically generate the release tag message with
the unreleased changes from the changelog.
Link: https://keepachangelog.com/en/1.0.0/
Signed-off-by: Robin Jarry <robin@jarry.cc>
