[ci] Run py_lint on template.

test/python.yml

@@ -17,3 +17,13 @@ py_tests:
     matrix:
       - PROJECT_ROOT: "test/python-template"
         EXIT_CODE: 0
+
+py_lint:
+  before_script:
+    - !reference [.ci-setup, script]
+    - cd $PROJECT_ROOT
+    - !reference [default, before_script]
+  parallel:
+    matrix:
+      - PROJECT_ROOT: "test/python-template"
+        EXIT_CODE: 0