Bug report

Syntax error when downloading/installing jquery-ui

I am trying to install some software that depends on Matplotlib. When I run the installation script, matplotlib installation throws this error.

Code for reproduction

```pip3 install matplotlib --user````

Actual outcome

    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-y0fnsonx/matplotlib/setup.py", line 139
        raise IOError(f"Failed to download jquery-ui.  Please download "
                                                                       ^
    SyntaxError: invalid syntax

    ----------------------------------------

Matplotlib version

Ubuntu 16.04 (Windows Subsystem for Linux)
Matplotlib 3.2.1
Python version 3.7

Installing matplotlib using sudo apt-get install python3-matplotlib works fine though.