Fix file extension

Author: vgvassilev

_data/contributors.yml

@@ -277,7 +277,7 @@
       mentors: Martin Vassilev, Jonas Rembser, Fons Rademakers, Vassil Vassilev
 
 - name: Petro Mozil
-  photo: PetroMozil.jpeg
+  photo: PetroMozil.jpg
   info: "Google Summer of Code 2025 Contributor"
   email: [email protected]
   education: "Bachelor of Computer Science, Ukrainian Catholic University, Ukraine"