Package version conflict

Error occurred when doing pip install on the requirements file:

The conflict is caused by:
The user requested attrs==20.3.0
cattrs 1.10.0 depends on attrs>=20
jsii 1.54.0 depends on attrs~=21.2

When the version pins were loosened, another error below occurs:

Collecting functools32>=3.2.3
Downloading functools32-3.2.3-2.zip (34 kB)
Preparing metadata (setup.py) ... error
error: subprocess-exited-with-error

× python setup.py egg_info did not run successfully.
│ exit code: 1
╰─> [1 lines of output]
This backport is for Python 2.7 only.
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.