Fix travis

Signed-off-by: Michal Konečný <mkonecny@redhat.com>

.travis.yml

@@ -14,8 +14,6 @@ env:
     - PYTHONWARNINGS=always::DeprecationWarning
   matrix:
     - TOXENV=lint
-    - TOXENV=bandit
-    - TOXENV=black
 matrix:
   include:
     - python: 3.6
@@ -30,5 +28,9 @@ matrix:
       sudo: required    # required for Python 3.8 (travis-ci/travis-ci#9069)
     - python: 3.6
       env: TOXENV=docs
+    - python: 3.6
+      env: TOXENV=bandit
+    - python: 3.6
+      env: TOXENV=black
   allow_failures:
     - python: nightly