base: Bump the nrf-regtool version to 5.3.0

The new version is required for the introduction of nRF MCAN:
zephyrproject-rtos/zephyr#73386

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

Dockerfile.base

@@ -114,7 +114,7 @@ RUN python3 -m pip install -U --no-cache-dir pip && \
 		-r https://raw.githubusercontent.com/zephyrproject-rtos/mcuboot/main/scripts/requirements.txt \
 		GitPython imgtool junitparser numpy protobuf PyGithub \
 		pylint sh statistics west \
-		nrf-regtool>=5.2.0 && \
+		nrf-regtool>=5.3.0 && \
 	pip3 check
 
 # Clean up stale packages