Add --upgrade to pip3 installation to upgrade necessary packages that…

… may already be installed.

PiperOrigin-RevId: 287577423
Change-Id: I3a6ac9b2d7af47ca0616fc89ec3faff38249198d

open_spiel/scripts/travis_script.sh

@@ -17,18 +17,14 @@
 set -e
 set -x
 
-# Need this to be able to install TF >= 1.15 on Ubuntu 18.04.
-sudo pip3 install --upgrade pip
-sudo pip3 install --upgrade setuptools
-
 virtualenv -p python ./venv
 source ./venv/bin/activate
 
 python --version
 
 pip3 install --upgrade pip
 pip3 install --upgrade setuptools
-pip3 install -r requirements.txt -q
+pip3 install --upgrade -r requirements.txt -q
 
 ./open_spiel/scripts/build_and_run_tests.sh
 deactivate