doc: release: 2.7: add release notes for serial

dcpleung · cfriedt · commit 7c62429a75e8 · 2021-10-01T20:35:11.000-04:00
Add release notes for serial/UART drivers based on commit
history.

Signed-off-by: Daniel Leung &lt;daniel.leung@intel.com&gt;
diff --git a/doc/releases/release-notes-2.7.rst b/doc/releases/release-notes-2.7.rst
@@ -386,6 +386,11 @@ Drivers and Sensors
 
 * Serial
 
+  * Added kconfig to disable runtime re-configuration of UART
+    to reduce footprint if so desired.
+  * Added ESP32-C3 polling only UART driver.
+  * Added ESP32-S2 polling only UART driver.
+  * Added Microchip XEC UART driver.
 
 * SPI
 
