chore: Python 3.12 is the floor, part A (#6)

The shared workflow tests on 3.12 and 3.13 by default and runs lowest on
3.12; the template declares requires-python >=3.12 with ruff and mypy on
3.12, and the tool itself needs 3.12. netOrk runs every driver on 3.12 in
its own containers.

check keeps accepting a 3.10 floor until every driver has moved; part B
raises it.

template/pyproject.toml

@@ -8,7 +8,7 @@ version = "0.1.0"
 description = "NAPALM driver for Example switches"
 readme = "README.md"
 license = "Apache-2.0"
-requires-python = ">=3.10"
+requires-python = ">=3.12"
 authors = [{ name = "Christian Manivong", email = "christian@manivong.de" }]
 classifiers = [
     "Programming Language :: Python :: 3",
@@ -38,7 +38,7 @@ napalm_example = ["py.typed"]
 
 [tool.ruff]
 line-length = 100
-target-version = "py310"
+target-version = "py312"
 
 [tool.ruff.lint]
 select = ["E", "F", "I", "UP", "B"]
@@ -48,7 +48,7 @@ select = ["E", "F", "I", "UP", "B"]
 "tests/**" = ["E501"]
 
 [tool.mypy]
-python_version = "3.10"
+python_version = "3.12"
 strict = true
 # napalm itself is untyped, so every driver subclasses Any.
 disallow_subclassing_any = false