Commit updates to "release-tools" repository:
[x] increase version number in "version" file to 19.12.0
[x] change "fromVersion=" in "create_log.py" file to v19.08.3 (previouss stable)
[x] change download URLs to "stable" in "create_sources_inc"
Prepare repositories to be released:
[x] run ./increase_repos_version.sh in your local machine
[ ] run ./add_appstream_version.sh in your local machine
[ ] check CI for build errors at https://build.kde.org/job/Applications/view/Everything%20-%20stable-kf5-qt5/
[ ] more?
Prepare tarballs:
[ } TBD
On release day:
[ } TBD