Merge branch 'changelog_2.9' into 'dev'

docs: Create changelog for Re2o 2.9

See merge request !590
1 job for dev in 27 seconds (queued for 3 seconds)
Name Stage Failure
lint Lint
W: The repository ' stretch-updates InRelease' is not signed.
W: GPG error: stretch Release: At least one invalid signature was encountered.
W: The repository ' stretch Release' is not signed.
$ DEBIAN_FRONTEND=noninteractive apt-get -qq install -y locales python3-django python3-pylint-django
E: You don't have enough free space in /var/cache/apt/archives/.
Running after_script
/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
Uploading artifacts for failed job
ERROR: Job failed: exit code 1