do not upgrade pip

Han Wang · Han Wang · commit 3b82e23878ff · 2020-01-23T07:46:21.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -72,7 +72,7 @@ matrix:
       - CXX=g++-8
       - TENSORFLOW_VERSION=2.0
 before_install:
-  - pip install --upgrade pip
+#  - pip install --upgrade pip
   - pip install --upgrade setuptools
   - pip install tensorflow==$TENSORFLOW_VERSION
 install:
