Use latest version of pip on travis.
@@ -62,7 +62,7 @@ matrix:
- python3 ./contrib/trigger_rtd_build.py
install:
- - pip install --upgrade "pip==19.2.1"
+ - pip install --upgrade "pip==19.3.1"
- pip install --upgrade "setuptools==42.0.2"
- pip install "virtualenv==16.7.6"
- pip install "tox==3.14.2"
