ERROR: Could not build wheels for backports.zoneinfo, which is required to install pyproject.toml-based projects

Avoid installing backports.zoneinfo when using python >= 3.9

Edit your requirements.txt file

FROM:

backports.zoneinfo==0.2.1

TO:

backports.zoneinfo;python_version<"3.9"

OR:

backports.zoneinfo==0.2.1;python_version<"3.9"

You can read more about this here and here