Merge branch 'announce-tet-ruleset' into 'master'

Ansgar Burchardtrequested to merge
cherry-pick-2c8b4296 into releases/2.6

Mention the new TET_RULESET flag in the changelog

See merge request !80 (merged)

(cherry picked from commit 2c8b4296)

5307aa43 Mention the new TET_RULESET flag in the changelog

Merge request reports