upgrade pip to ensure cibuildwheel latest is used

rnpridgeon · rnpridgeon · commit 3f682eed811a · 2020-05-29T06:53:50.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -44,6 +44,7 @@ jobs:
 # Travis OSX envs requires some setup; see tools/prepare-osx.sh
 # Install cibuildwheel if this is a tagged PR
 before_install:
+  - pip install -U pip
   - if [[ $TRAVIS_OS_NAME == "osx" ]]; then tools/prepare-osx.sh ${INTERPRETER_VERSION} /tmp/venv && source /tmp/venv/bin/activate; fi
   - if [[ -n $TRAVIS_TAG && -n $CIBW_BEFORE_BUILD ]]; then pip install cibuildwheel --force-reinstall; fi
 
