Pin mypy.

packages/test.sh

@@ -14,7 +14,7 @@ TEST_ENV_DIR=${TEST_ENV_DIR:-$(mktemp -d -t gxpkgtestenvXXXXXX)}
 
 virtualenv -p "$TEST_PYTHON" "$TEST_ENV_DIR"
 . "${TEST_ENV_DIR}/bin/activate"
-pip install mypy
+pip install "mypy==0.790"
 
 # ensure ordered by dependency dag
 PACKAGE_DIRS=(

tox.ini

@@ -30,7 +30,7 @@ setenv =
 deps =
     lint,lint_docstring,lint_docstring_include_list: -rlib/galaxy/dependencies/pipfiles/flake8/pinned-requirements.txt
     unit: mock-ssh-server
-    mypy: mypy
+    mypy: mypy==0.790
 
 [testenv:mulled]
 commands =  bash run_tests.sh --skip-venv -u test/unit/tool_util/mulled