specify requests 2.9.2 to work around a bug in linkchecker

diff --git a/build-scripts/travis.sh b/build-scripts/travis.sh
index f556ae9d84cca56a5bffa754e8b72e8d8ed4d696..e32b5b1bc69c97976e6168aac54a573a31c1a195 100755 (executable)
--- a/build-scripts/travis.sh
+++ b/build-scripts/travis.sh
@@ -320,7 +320,7 @@ install_docs() {
   # documentation test requirements
   run "virtualenv $HOME/.venv"
   run "source $HOME/.venv/bin/activate"
-  run "pip install -q pandocfilters==1.2.3 mkdocs==0.14 linkchecker==9.3 click==5.1"
+  run "pip install -q pandocfilters==1.2.3 mkdocs==0.14 linkchecker==9.3 click==5.1 requests==2.9.2"
   run "deactivate"
 }