Add GeomFuM paper entry to bibliography

Added a new entry for the GeomFuM paper in the bibliography.

Author: GiLonga

_bibliography/papers.bib

@@ -3,6 +3,15 @@
 
 @string{aps = {American Physical Society,}}
 
+@unknown{unknown,
+author = {Viganò, Giulio and Longari, Giorgio and Pereira, Luís and Miolane, Nina and Melzi, Simone},
+year = {2025},
+month = {09},
+pages = {},
+title = {GeomFuM: A Python Package for Machine Learning with Functional Maps},
+doi = {10.13140/RG.2.2.31903.01441}
+}
+
 @InProceedings{10.1007/978-3-032-05185-1_63,
 author="Maccarone, Francesca
 and Longari, Giorgio