Update appveyor.yml

Attempt to work around old version of nose that doesn't work with later versions of Python.  Will it work?

Signed-off-by: Michael Tiemann <72577720+MichaelTiemannOSC@users.noreply.github.com>

Author: MichaelTiemannOSC

appveyor.yml

@@ -47,7 +47,7 @@ install:
   - conda init cmd.exe
   - conda info -a
   # Create a conda virtual environement 
-  - "conda create -n uncty-env numpy nose python=%PYTHON_VERSION%"
+  - "conda create -n uncty-env numpy nose=1.3.7=py_1006 python=%PYTHON_VERSION%"
   - activate uncty-env