packager/docker-cli: bump version to 19.03.7

To match the docker-engine version.

./support/testing/run-tests tests.package.test_docker_compose.TestDockerCompose
09:54:39 TestDockerCompose                        Starting
09:54:40 TestDockerCompose                        Building
10:45:33 TestDockerCompose                        Building done
10:46:30 TestDockerCompose                        Cleaning up
.
----------------------------------------------------------------------
Ran 1 test in 3121.828s

OK

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>