Move linting to its own stage, install python-is-python3 in setup

.gitlab-ci.yml

@@ -1,11 +1,12 @@
 image: ubuntu:focal
 stages:
+  - lint
   - test
   - play
 before_script:
   # Get the packages we need
   - apt-get update
-  - apt-get install openssh-client python3-docker python3-pip -y
+  - apt-get install openssh-client python3-docker python3-pip python-is-python3 -y
   - pip install ansible ansible-lint
   # Dump our key
   - eval $(ssh-agent -s)
@@ -23,7 +24,7 @@ before_script:
 
 Lint:
   allow_failure: yes
-  stage: test
+  stage: lint
   script:
     - ansible-lint --version
     - ansible-lint site.yml