python3Packages.update_checker: disable py2
```
builder for '/nix/store/2qwl0rkdm2gx2byhpmw7lxyg5rprwqqk-python2.7-update_checker-0.18.0.drv' failed with exit code 1; last 10 log lines:
no configure script, doing nothing
building
Executing setuptoolsBuildPhase
Traceback (most recent call last):
File "nix_run_setup", line 8, in <module>
exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\\r\\n', '\\n'), __file__, 'exec'))
File "setup.py", line 9
with open(f"{MODULE_NAME}.py") as fp:
^
SyntaxError: invalid syntax
```
92c7a40856