Fix clean makefile target (#11)

* Fix clean makefile target

* Add makefile support for custom docker image

Makefile

@@ -1,6 +1,7 @@
 .PHONY: all ${MAKECMDGOALS}
 
 MOLECULE_SCENARIO ?= ubuntu
+MOLECULE_DOCKER_IMAGE ?= ubuntu2004
 GALAXY_API_KEY ?=
 GITHUB_REPOSITORY ?= $$(git config --get remote.origin.url | cut -d: -f 2 | cut -d. -f 1)
 GITHUB_ORG = $$(echo ${GITHUB_REPOSITORY} | cut -d/ -f 1)
@@ -33,13 +34,13 @@ collections:
 requirements: roles collections
 
 dependency create prepare converge idempotence side-effect verify destroy login reset:
-	poetry run molecule $@ -s ${MOLECULE_SCENARIO}
+	MOLECULE_DOCKER_IMAGE=${MOLECULE_DOCKER_IMAGE} poetry run molecule $@ -s ${MOLECULE_SCENARIO}
 
 ignore:
 	poetry run ansible-lint --generate-ignore
 
 clean: destroy reset
-	poetry env remove $$(which python)
+	@poetry env remove $$(which python) >/dev/null 2>&1 || exit 0
 
 publish:
 	@echo publishing repository ${GITHUB_REPOSITORY}