default This setMapKeyColumn(String keyColumn) {
        return configure(MapEntryMappers.class, c -> c.setKeyColumn(keyColumn));
    }
Convenience method for {@code getConfig(MapEntryMappers.class).setKeyColumn(keyColumn)}

@param keyColumn the key column name
@return this
core/src/main/java/org/jdbi/v3/core/config/Configurable.java