add feature overrides for new example

Author: jlogan03

Cargo.toml

@@ -215,6 +215,10 @@ required-features = ["rt", "stm32h747cm7", "ethernet"]
 name = "ethernet-rtic-stm32h735g-dk"
 required-features = ["rt", "stm32h735", "ethernet"]
 
+[[example]]
+name = "ethernet-rtic-nucleo-h723zg"
+required-features = ["rt", "stm32h735", "ethernet"]
+
 [[example]]
 name = "ethernet-nucleo-h743zi2"
 required-features = ["rt", "revision_v", "stm32h743v", "ethernet"]