fix: STM32F7 CMSIS device drivers version is 1.2.8

Signed-off-by: Frederic Pillon <[email protected]>

Author: fpistm

system/Drivers/CMSIS/Device/ST/STM32YYxx_CMSIS_version.md

@@ -5,7 +5,7 @@
   * STM32F2: 2.2.5
   * STM32F3: 2.3.6
   * STM32F4: 2.6.8
-  * STM32F7: 1.2.7
+  * STM32F7: 1.2.8
   * STM32G0: 1.4.3
   * STM32G4: 1.2.2
   * STM32H7: 1.10.2