docs: Update copyright text's date

Author: jcs090218

docs/siradoc.yml

@@ -25,7 +25,7 @@ version_num_06: ''
 version_num_07: ''
 
 # Copyright
-copyright_text: 'Copyright © 2025 JCSUnity Group. Built: 2025-01-01.'
+copyright_text: 'Copyright © 2025 JCSUnity Group. Built: 2025-04-11.'
 
 # Link
 homepage_url: 'https://github.com/jcs090218/JCSUnity'