Update appveyor.yml

Author: mottosso

appveyor.yml

@@ -3,4 +3,4 @@ environment:
     - PYTHON: "C:\\Python27-x64"
 
 install:
-  - "%PYTHON%\\python.exe -m pip install git+git://github.com/pyqt/python-qt5.git
+  - "%PYTHON%\\python.exe -m pip install git+git://github.com/pyqt/python-qt5.git"