doc: add openocd as a dependency for mac

openocd is not part of the mac Zephyr SDK, so it should be installed
through brew

Signed-off-by: Toon Stegen <[email protected]>

Author: toonst

doc/develop/getting_started/index.rst

@@ -132,7 +132,7 @@ The current minimum required version for the main dependencies are:
 
          .. code-block:: bash
 
-            brew install cmake ninja gperf python3 ccache qemu dtc libmagic wget
+            brew install cmake ninja gperf python3 ccache qemu dtc libmagic wget openocd
 
       #. Add the Homebrew Python folder to the path, in order to be able to
          execute ``python`` and ``pip`` as well ``python3`` and ``pip3``.