codedFunctionObjectTemplate: Added #include "volFields.H"

The codedFunctionObjectTemplate is based on regionFunctionObject requiring
fvMesh.H and most manipulate volFields so it makes sense for volFields.H to be
included by default.

etc/codeTemplates/dynamicCode/codedFunctionObjectTemplate.C

@@ -24,6 +24,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "codedFunctionObjectTemplate.H"
+#include "volFields.H"
 #include "unitConversion.H"
 #include "addToRunTimeSelectionTable.H"