Implement cylinder flow dataset

Author: GuillaumeBroggi

.gitignore

@@ -173,10 +173,13 @@ projects/
 !benchmarks/utils/utils.py
 benchmarks/mechanics/gnn_shell_buckling/*
 !benchmarks/mechanics/gnn_shell_buckling/gnn_shell_buckling.ipynb
-!benchmarks/mechanics/gnn_shell_buckling/gnn_shell_buckling.svg
+!benchmarks/mechanics/gnn_shell_buckling/_assets
 benchmarks/cfd/gnn_porous_medium/*
 !benchmarks/cfd/gnn_porous_medium/gnn_porous_medium.ipynb
-!benchmarks/cfd/gnn_porous_medium/gnn_porous_medium.svg
+!benchmarks/cfd/gnn_porous_medium/_assets
+benchmarks/cfd/mgn_cylinder_flow/*
+!benchmarks/cfd/mgn_cylinder_flow/gnn_cylinder_flow.ipynb
+!benchmarks/cfd/mgn_cylinder_flow/_assets
 
 # Sphinx docs
 docs/source/_autosummary