Update prance to 0.15.0
@@ -478,7 +478,7 @@ requirements: virtualenv .sdist-requirements install-runners
# Note: We install prance here and not as part of any component
# requirements.txt because it has a conflict with our dependency (requires
# new version of requests) which we cant resolve at this moment
- $(VIRTUALENV_DIR)/bin/pip install "prance==0.6.1"
+ $(VIRTUALENV_DIR)/bin/pip install "prance==0.15.0"
# Install st2common to register metrics drivers
# NOTE: We pass --no-deps to the script so we don't install all the
