I faced the same problem on Ubuntu 19.04, running Python 3.7.3. I used the following command to get rid of the dateutil error
pip install -U python-dateutil==2.80
and then encountered the httptools build fail error. To solve that I ran
sudo apt-get install python3-dev
To reinstall the header files and static libraries for python dev.
I ran pip install rasa again after two commands above and it works.