rtio: API version 0.2.0, unstable

We're well past the experimental stage, but there are still some things
that may change. Bumping the API version to 0.2.0 signals this.

Signed-off-by: Tom Burdick <thomas.burdick@intel.com>

include/zephyr/rtio/rtio.h

@@ -48,7 +48,7 @@ extern "C" {
  * @brief RTIO
  * @defgroup rtio RTIO
  * @since 3.2
- * @version 0.1.0
+ * @version 0.2.0
  * @ingroup os_services
  * @{
  */