Install OCP stubs for Windows too

Author: jmwright

appveyor.yml

@@ -50,7 +50,7 @@ install:
     - sh: conda install -c conda-forge -c defaults -c cadquery cadquery=master python=$PYTHON_VERSION
     - conda install black=19.10b0
     - conda install mypy
-    - sh: pip install git+https://github.com/CadQuery/[email protected]
+    - pip install git+https://github.com/CadQuery/[email protected]
 
 build: false