AppVeyor: bump PyQt5/SIP maybe solves segfault?

Author: kernc

appveyor.yml

@@ -21,7 +21,7 @@ environment:
     BUILD_GLOBAL_OPTIONS: build -j1
     BUILD_ENV: wheel==0.29.0 pip==9.0.1 numpy==1.9.3
     # SIP 4.19.4+ with PyQt5==5.9.1+ segfault our tests (GH-2756)
-    TEST_ENV: sip==4.19.3 PyQt5==5.9 numpy==1.12.1 scipy==1.0.0b1 scikit-learn
+    TEST_ENV: sip==4.19.6 PyQt5==5.9.2 numpy==1.12.1 scipy==1.0.0b1 scikit-learn
 
   matrix:
     - PYTHON: C:\Python34