doc: develop: api: overview: note that the CAN API was changed in v3.1

Update the API overview documentation to note that the CAN API was
changed in the upcoming Zephyr v3.1 release.

Signed-off-by: Henrik Brix Andersen <[email protected]>

Author: henrikbrixandersen

doc/develop/api/overview.rst

@@ -50,7 +50,7 @@ current :ref:`stability level <api_lifecycle>`.
    * - :ref:`can_api`
      - Unstable
      - 1.14
-     - 3.0
+     - 3.1
 
    * - :ref:`counter_api`
      - Unstable