Travis: fix shell syntax for version specifier
@@ -52,7 +52,7 @@ addons:
# To install dependencies, tell tox to do everything but actually running the
# test.
install:
- - travis_retry pip install tox<=3.8.1 sphinx
+ - travis_retry pip install 'tox<=3.8.1' sphinx
# upgrade requests to satisfy sphinx linkcheck (for building man pages)
- if [[ $TRAVIS_PYTHON_VERSION == *_site_packages ]]; then pip install -U requests; fi
- travis_retry tox -e $TOX_ENV --notest
