upd some versioning files

Context

• upd 'version.txt'
• upd 'Changelog'
• upd catch2 version

assigned to @pineapple

added 81 commits

• 56ac694b...8a48ba0b - 79 commits from branch dev
• 1908686b - v0.4.0 - Merge branch 'dev' into 'main'
• f489e0e4 - upd version 0.3.2 -> 0.4.0

Compare with previous version

enabled an automatic merge when all merge checks for f489e0e4 pass

merged

mentioned in commit e23d88c8