New build of micropython

tools/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:22.04
 
 ARG DEBIAN_FRONTEND=noninteractive
 

tools/update-micropython.sh

@@ -1,6 +1,10 @@
+#!/bin/bash
 # this script updates the micropython binary in the /bin directory that is
 # used to run unit tests under GitHub Actions builds
-docker build -t micropython .
-docker create -it --name dummy-micropython micropython
-docker cp dummy-micropython:/usr/local/bin/micropython ../bin/micropython
-docker rm dummy-micropython
+
+DOCKER=${DOCKER:-docker}
+
+$DOCKER build -t micropython .
+$DOCKER create -it --name dummy-micropython micropython
+$DOCKER cp dummy-micropython:/usr/local/bin/micropython ../bin/micropython
+$DOCKER rm dummy-micropython