v0.3.1

DispersiveShallowWater v0.3.1

Diff since v0.3.0

Merged pull requests:

• Use trixi_include from TrixiBase.jl (#88) (@JoshuaLampert)
• Fix formatter version (#89) (@JoshuaLampert)
• Downgrade action moved (#90) (@JoshuaLampert)
• Fix initial condition from Dingemans experiment for BBM-BBM equations (#91) (@JoshuaLampert)