fix: the floor on napalm is 5.1 (NAPALM/driver-standard#6)

napalm 5.0 and older import pkg_resources, which a Python 3.12 venv no
longer has, so the lowest job failed on them.

CHANGELOG.md

@@ -9,6 +9,8 @@ All notable changes to this driver. The format follows
 ### Changed
 - Python 3.12 is the floor (`requires-python = ">=3.12"`): netOrk runs every driver
   on 3.12, so 3.10 and 3.11 are no longer tested (NAPALM/driver-standard#6).
+- The floor on napalm is 5.1: older releases import `pkg_resources`, which a Python
+  3.12 venv no longer has.
 
 ## [0.3.0] - 2026-10-23