west: Point back to main after release

After releasing v3.2.0, move back to main.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

Author: fabiobaltieri

west.yml

@@ -13,5 +13,5 @@ manifest:
   projects:
     - name: zephyr
       remote: zephyrproject-rtos
-      revision: v3.2.0
+      revision: main
       import: true