Add Python 3.12 to the default interpreter universe (#19641)

[PEP 693](https://peps.python.org/pep-0693/) gives an expected release
date for 3.12.0 of 2023-10-02, which is about 6 weeks away. This
suggests it's likely that either Pants 2.17 or 2.18 will be the current
Pants release when 3.12.0 comes out... This patch anticipates this, and
ensures Pants users are ready to start using 3.12.0 immediately, easily,
without having to override the `[python] interpreter_versions_universe =
...` setting.

I'm not sure if changing this value has consequences beyond just making
more options available; let me know! I also don't know what `category:`
label this should have.

Co-authored-by: Benjy Weinberger <benjyw@gmail.com>

src/python/pants/backend/python/subsystems/setup.py

@@ -64,7 +64,17 @@ class PythonSetup(Subsystem):
     options_scope = "python"
     help = "Options for Pants's Python backend."
 
-    default_interpreter_universe = ["2.7", "3.5", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+    default_interpreter_universe = [
+        "2.7",
+        "3.5",
+        "3.6",
+        "3.7",
+        "3.8",
+        "3.9",
+        "3.10",
+        "3.11",
+        "3.12",
+    ]
 
     _interpreter_constraints = StrListOption(
         default=None,