need to allow setting the DOE Discovery Version

[lazineer]

The DOE Discovery Version changes based on the Capability Version in the Data Object Exchange Extended Capability.
Currently, DOE_DISCOVERY_VERSION is fixed at 0.

spdm-emu/spdm_emu/spdm_device_validator_sample/spdm_device_validator_pci_doe.c

Lines 10 to 24 in 8e33385

	#define DOE_DISCOVERY_VERSION 0
	libspdm_return_t pci_doe_init_request()
	{
	pci_doe_data_object_protocol_t data_object_protocol[6];
	size_t data_object_protocol_size;
	libspdm_return_t status;
	uint32_t index;
	data_object_protocol_size = sizeof(data_object_protocol);
	status =
	pci_doe_discovery (m_pci_doe_context, data_object_protocol, &data_object_protocol_size, DOE_DISCOVERY_VERSION);
	if (LIBSPDM_STATUS_IS_ERROR(status)) {
	return status;
	}

It would be good if it could be set as a parameter in spdm_emu.

[jyao1]

Feel free to propose a change with PR