WIP: Install cloudpickle with pickle5 support

Author: jakirkham

continuous_integration/travis/install.sh

@@ -74,6 +74,7 @@ fi
 if [[ $PYTHON != 3.8 ]]; then
     # Install backport package for pickle protocol 5 support
     conda install -c conda-forge -c defaults 'pickle5>=0.0.10'
+    pip install git+https://github.com/jakirkham/cloudpickle.git@opt_use_pickle5_redux
     # stacktrace is not currently avaiable for Python 3.8.
     # Remove the version check block below when it is avaiable.
     # For low-level profiler, install libunwind and stacktrace from conda-forge