Use a fork of universal-analytics-python that supports Python 3

The current version is dead since 2 years and is Python 2 only.
Fortunately, a company forked and ported the module to Python 3: https://github.com/GoodRx/universal-analytics-python

Simple swicth to that version. As there is no module availability on PyPi, we could use a full link in the requirements: https://github.com/GoodRx/universal-analytics-python/archive/0.2.5.zip (may be needed to adjust the version).

There should be no additional work to do, the drop-in replacement should work as is.