Something changed yesterday in the macOS environments that broke Python3:
pip3 install --user beautifulsoup4 lxml
/Users/travis/.travis/functions: /usr/local/bin/pip3: /usr/local/opt/python/bin/python3.7: bad interpreter: No such file or directory
This worked until yesterday at least on xCode 11.3, 10.3 and 9.4 images: https://travis-ci.com/github/rweickelt/qbs/builds/174729698
python3 -m pip instead of
pip3 makes it work on the xCode 11.3 image, but not on older ones.