update CHANGELOG.md

CHANGELOG.md

 # Change log
 
+## v2.4 (2023-05-02)
+
+- phd option according to department standards
+- separate examples for phd and student thesis
+- birthplace command added (optional for student thesis)
+- nodayofweek option in package datetime
+
 ## v2.3 (2023-03-31)
 
 - phd class option added