CI: Pin CPython to 3.6.6 (pandas-dev#23322)

TomAugspurger · tm9k1 · commit 07100016f223 · 2018-11-20T02:37:20.000+05:30
diff --git a/ci/azure-windows-36.yaml b/ci/azure-windows-36.yaml
@@ -16,7 +16,7 @@ dependencies:
   - pyarrow
   - pytables
   - python-dateutil
-  - python=3.6.*
+  - python=3.6.6
   - pytz
   - scipy
   - thrift=0.10*
