doc: release-notes-3.7: add ctcc/nrf52840

Add ctcc/nrf52840 entry to newly added boards.

Signed-off-by: Jan Kowalewski <jkowalewski@cthings.co>

Author: kowalewskijan

doc/releases/release-notes-3.7.rst

@@ -437,6 +437,7 @@ Boards & SoC Support
   * Added support for :ref:`Espressif ESP32-C6 DevKit-C <esp32c6_devkitc>`: ``esp32c6_devkitc``.
   * Added support for :ref:`Waveshare ESP32-S3-Touch-LCD-1.28 <esp32s3_touch_lcd_1_28>`: ``esp32s3_touch_lcd_1_28``.
   * Added support for :ref:`M5Stack ATOM Lite <m5stack_atom_lite>`: ``m5stack_atom_lite``.
+  * Added support for :ref:`CTHINGS.CO Connectivity Card nRF52840 <ctcc_nrf52840>`: ``ctcc_nrf52840``.
 
 * Made these board changes: