feat: version 0.2.3

Description

• Raise CLI version constant to match upcoming release version (we should use tags instead in the future).
• Delete CHANGELOG.md to use release notes instead.
• Rename LICENSE.txt to LICENSE.

Related issue

Examples

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes, specifications reflect those changes and they have been reviewed OR there are no API changes