fix corsika-data submodule

Make the corsika-data submodule point to the most recent commit.

I am a bit confused why this didn't work before. In the last PR (!600 (merged)), I did a commit which should have updated the submodule: !600 (32773c52)

But somehow, the master still points at this state: https://gitlab.iap.kit.edu/AirShowerPhysics/corsika-data/-/tree/331c0aad7c6c17fe456c4a80f8b2575ef341ce90

I guess something went wrong earlier.

modules/data

-Subproject commit 331c0aad7c6c17fe456c4a80f8b2575ef341ce90
+Subproject commit 81eab5761247ecd4caa99983688e8ec86b82cf5e