Update CHANGELOG.md with 1.74.0 release notes.
Update CHANGELOG.md with 1.74.0 release notes.

jonvestal/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,jonvestal/open-kilda,jonvestal/open-kilda,telstra/open-kilda,jonvestal/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,jonvestal/open-kilda