[Nephos] Upgrade SAI to v1.2.3 (#1494)

- What I did
Upgrading SAI version from v1.0 to v1.2.3

- How I did it
Updating platform/nephos/sai.mk

- How to verify it
Checking the image can build successfully in the branch master

- Description for the changelog
Upgrade SAI to v1.2.3

- A picture of a cute animal (not mandatory but encouraged)

Signed-off-by: Sam Yang <yang.kaiyu@gmail.com>

platform/nephos/sai.mk

@@ -1,9 +1,9 @@
 NEPHOS_SAI = libsainps_2.0.3_amd64.deb
 $(NEPHOS_SAI)_URL = "https://github.com/NephosInc/SONiC/raw/master/sai/libsainps_2.0.3_amd64.deb"
 
-NEPHOS_SAI_DEV = libsainps-dev_2.0.3a63-20180110_amd64.deb
+NEPHOS_SAI_DEV = libsainps-dev_2.0.3_sai_1.2.3_amd64.deb
 $(eval $(call add_derived_package,$(NEPHOS_SAI),$(NEPHOS_SAI_DEV)))
-$(NEPHOS_SAI_DEV)_URL = "https://github.com/NephosInc/SONiC/raw/master/sai/libsainps-dev_2.0.3a63-20180110_amd64.deb"
+$(NEPHOS_SAI_DEV)_URL = "https://github.com/NephosInc/SONiC/raw/master/sai/libsainps-dev_2.0.3_sai_1.2.3_amd64.deb"
 
 SONIC_ONLINE_DEBS += $(NEPHOS_SAI) $(NEPHOS_SAI_DEV)
 $(NEPHOS_SAI_DEV)_DEPENDS += $(NEPHOS_SAI)