README update STM32G4 to CUBE V1.4.0

Author: JeanMarcR

targets/TARGET_STM/README.md

@@ -68,7 +68,7 @@ This table summarizes the STM32Cube versions currently used in Mbed OS master br
 | F4          |    1.26.0    | https://github.com/STMicroelectronics/STM32CubeF4 |
 | F7          |    1.16.0    | https://github.com/STMicroelectronics/STM32CubeF7 |
 | G0          |    1.4.1     | https://github.com/STMicroelectronics/STM32CubeG0 |
-| G4          |    1.1.0     | https://github.com/STMicroelectronics/STM32CubeG4 |
+| G4          |    1.4.0     | https://github.com/STMicroelectronics/STM32CubeG4 |
 | H7          |    1.8.0     | https://github.com/STMicroelectronics/STM32CubeH7 |
 | L0          |    1.11.3    | https://github.com/STMicroelectronics/STM32CubeL0 |
 | L1          |    1.10.2    | https://github.com/STMicroelectronics/STM32CubeL1 |