Make mypy a dev dependency (#263)

* make mypy a dev dependency

* use poetry 1.0.0 to update poetry.lock

Author: rschwanhold

poetry.lock

@@ -19,13 +19,13 @@ psutil = "^5.6.7"
 nibabel = "^2.5.1"
 scikit-image = "^0.16.2"
 scikit-learn = "^0.24.0"
-mypy = "^0.770"
 
 [tool.poetry.dev-dependencies]
 pylint = "^2.6.0"
 black = "^20.8b1"
 pytest = "^6.2.1"
 setuptools-scm = "^3.3.3"
+mypy = "^0.770"
 
 [build-system]
 requires = ["poetry>=0.12"]