Update config for breaking change in Tox 4.0.6 (ansible#150)

tox-dev/tox#2676 for details.

Signed-off-by: Rick Elrod <rick@elrod.me>

tox.ini

@@ -8,8 +8,7 @@ install_command = pip install {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
 
 [testenv:podman]
-passenv =
-  HOME
+passenv = HOME
 allowlist_externals =
   /bin/bash
 commands =
@@ -18,17 +17,15 @@ commands =
 
 
 [testenv:docker]
-passenv =
-  HOME DOCKER_BUILDKIT
+passenv = HOME,DOCKER_BUILDKIT
 allowlist_externals =
   /bin/bash
 commands =
   /bin/bash -c "docker rmi quay.io/ansible/awx-ee:latest || true"
   ansible-builder build -v3 -c . -t quay.io/ansible/awx-ee {posargs} --container-runtime=docker
 
 [testenv:check-diff]
-passenv =
-  {[testenv:docker]passenv}
+passenv = {[testenv:docker]passenv}
 allowlist_externals =
   /bin/bash
   {toxinidir}/tools/check_ansible_builder_changed.sh