testing: update docker-py to 7.0.0b1

https://github.com/docker/docker-py/compare/6.1.3...7.0.0b1

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 4394c61e6c66bd7ad7ca85838a3019bbe730ede9)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

hack/make/test-docker-py

@@ -4,7 +4,7 @@ set -e
 source hack/make/.integration-test-helpers
 
 # The commit or tag to use for testing
-: "${DOCKER_PY_COMMIT:=6.1.3}"
+: "${DOCKER_PY_COMMIT:=7.0.0b1}"
 
 # The version (and variant) of the python image to use for the tests;
 # see https://github.com/docker/docker-py/blob/5.0.3/tests/Dockerfile#L1C5-L3