CI: Travis default to 3.7 (#30540)

ShaharNaveh · jreback · commit 59a148585cd1 · 2019-12-30T08:09:58.000-05:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,5 @@
 language: python
-python: 3.5
+python: 3.7
 
 # To turn off cached cython files and compiler cache
 # set NOCACHE-true
