use correct year (#1712)

Author: 20DM

_gsocproposals/2025/proposal_MCnetMCviz.md

@@ -2,7 +2,7 @@
 title: MCnet/MCviz - graph and 3D-viewer tools for simulated particle collisions
 layout: gsoc_proposal
 project: MCnet
-year: 2024
+year: 2025
 organization:
   - UofGlasgow
 difficulty: medium