Compatibility requirements for Flux relaxed | local tests pass

Author: MatthiasSachs

Project.toml

@@ -29,7 +29,7 @@ JuLIP = "0.16"
 StaticArrays = "1.0"
 julia = "1.11"
 CUDA = "5.8"
-Flux = "0.16"
+Flux = "0.14, 0.15, 0.16"  
 HDF5 = "0.17"
 KernelAbstractions = "0.9"
 NeighbourLists = "0.5"