ci: Disable Python 3.7 not yet available in appveyor image

See appveyor/ci#2475

Author: jcfr

appveyor.yml

@@ -49,15 +49,15 @@ environment:
       PYTHON_ARCH: "64"
       BLOCK: "0"
 
-    - PYTHON_DIR: "C:\\Python37"
-      PYTHON_VERSION: "3.7.x"
-      PYTHON_ARCH: "64"
-      BLOCK: "0"
-
-    - PYTHON_DIR: "C:\\Python37-x64"
-      PYTHON_VERSION: "3.7.x"
-      PYTHON_ARCH: "64"
-      BLOCK: "0"
+#    - PYTHON_DIR: "C:\\Python37"
+#      PYTHON_VERSION: "3.7.x"
+#      PYTHON_ARCH: "64"
+#      BLOCK: "0"
+#
+#    - PYTHON_DIR: "C:\\Python37-x64"
+#      PYTHON_VERSION: "3.7.x"
+#      PYTHON_ARCH: "64"
+#      BLOCK: "0"
 
   GIRDER_TOKEN:
     secure: BJR/8+Z51IgDgkwnKVkmzxxP315kpgy6r952X3P03bIe0YTNo1ZeOSeqqEvJwFQF