Try to run codechecks3 on CI

.circleci/config.yml

@@ -150,7 +150,7 @@ jobs:
             # Since this job is never scheduled this step is never run so the
             # actual value here is irrelevant.
 
-  lint:
+  codechecks:
     docker:
       - <<: *DOCKERHUB_AUTH
         image: "circleci/python:2"
@@ -168,6 +168,24 @@ jobs:
           command: |
             ~/.local/bin/tox -e codechecks
 
+  codechecks3:
+    docker:
+      - <<: *DOCKERHUB_AUTH
+        image: "circleci/python:3"
+
+    steps:
+      - "checkout"
+
+      - run:
+          name: "Install tox"
+          command: |
+            pip install --user tox
+
+      - run:
+          name: "Static-ish code checks"
+          command: |
+            ~/.local/bin/tox -e codechecks3
+
   pyinstaller:
     docker:
       - <<: *DOCKERHUB_AUTH