chore: update software version v2.8.1 and date in publiccode.yml

Co-authored-by: astagi <astagi@users.noreply.github.com>

publiccode.yml

@@ -72,8 +72,8 @@ maintenance:
 name: Bootstrap Italia
 platforms:
   - web
-releaseDate: '2023-12-15'
+releaseDate: '2023-12-18'
 roadmap: 'https://designers.italia.it/piano-attivita/'
 softwareType: library
-softwareVersion: v2.8.0
+softwareVersion: v2.8.1
 url: 'https://github.com/italia/bootstrap-italia'