MEM driver: declare field subtypes Boolean Int16 Float32 JSON UUID

Author: rouault

frmts/mem/memdataset.cpp

@@ -3479,6 +3479,8 @@ void GDALRegister_MEM()
         GDAL_DMD_CREATIONFIELDDATATYPES,
         "Integer Integer64 Real String Date DateTime Time IntegerList "
         "Integer64List RealList StringList Binary");
+    poDriver->SetMetadataItem(GDAL_DMD_CREATIONFIELDDATASUBTYPES,
+                              "Boolean Int16 Float32 JSON UUID");
     poDriver->SetMetadataItem(GDAL_DMD_CREATION_FIELD_DEFN_FLAGS,
                               "WidthPrecision Nullable Default Unique "
                               "Comment AlternativeName Domain");