UP036 doesn't handle three digit version numbers correctly

### Description

The following check:

```python
if sys.version_info < (3, 8, 7):
```

Should not be removed for Python `>=3.8`, but currently, it is - the check seems to ignore the third digit entirely. It should only be removed for `>=3.9`. Occurs in Python packaging related repos like scikit-build-core due to a bug in sysconfig fixed in 3.8.7.