manifest: NCS v3.1.0

Point to the NCS v3.1.0 release tag.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>

Author: carlescufi

west.yml

@@ -13,5 +13,5 @@ manifest:
     - name: nrf
       remote: ncs
       repo-path: sdk-nrf
-      revision: main
+      revision: v3.1.0
       import: true