Refactor release workflow and changelog generation

[sni10]

This pull request updates the GitHub Actions workflow for releases, focusing on simplifying the release process and improving changelog generation. The main changes are related to how tags and versions are handled, as well as how the changelog is generated.

Release workflow simplification and changelog improvement:

• The workflow now triggers only on new tags matching the pattern v*.*.*, instead of also running on pushes to main.
• The custom Get version step has been removed; the release now uses the tag name directly from the GitHub context for the release name. [1] [2]
• The changelog generation logic has been improved to select the previous tag more accurately by using the second most recent tag, ensuring the changelog reflects changes since the last release.