Merge branch 'mac-python' into 'master'

Fix python_coupling on recent macOS

See merge request walberla/walberla!303

src/python_coupling/Shell.h

@@ -22,6 +22,8 @@
 
 #pragma once
 
+#include <string>
+
 #include "waLBerlaDefinitions.h"
 #include "core/DataTypes.h"