docs: Update versioning in README.md

docs: Refactor README.md to use semantic versioning

This commit updates the project version number in the README file from "v2" to "v2.0.0" to align with semantic versioning standards.

Author: augusto-mate

README.md

@@ -21,5 +21,5 @@ Open `index.html` in any modern browser. No build step needed.
 ---
 **Assignment fit**: Part 1 (visual effects), Part 2 (functions & scope), Part 3 (integration via class toggling).
 
-### v2 Update
+### Version: v2.0.0 Update
 - Added **accessibility improvement**: modal can now be closed with the **Escape key**, in addition to click.