chore: Python 3.12 is the floor (NAPALM/driver-standard#6)

netOrk runs every driver in its own containers on Python 3.12, so 3.10
and 3.11 are no longer supported or tested. requires-python, mypy and
ruff move to 3.12, along with what ruff's pyupgrade rules then rewrite.

tests/test_fact_getters.py

@@ -30,8 +30,7 @@ def test_a_missing_license_may_say_what_the_device_withholds_without_it():
     # A Supermicro X10 with only SFT-OOB-LIC answers Redfish but keeps its drives and
     # firmware inventory until DCMS is activated: partly licensed, not unlicensed.
     hints = get_type_hints(LicenseDict)
-    # Python 3.10 keeps NotRequired[...] around the type; later versions strip it.
-    assert "list[str]" in str(hints["withholds"])
+    assert hints["withholds"] == list[str]
     assert "withholds" not in LicenseDict.__required_keys__