Actions: add Python 3.12 (released early Oct '23) runner

Author: sadielbartholomew

.github/workflows/run-test-suite.yml

@@ -25,7 +25,7 @@ jobs:
         # Skip older ubuntu-16.04 & macos-10.15 to save usage resource
         os: [ubuntu-latest, macos-latest]
         # Note: keep versions quoted as strings else 3.10 taken as 3.1, etc.
-        python-version: ["3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     # Run on new and old(er) versions of the distros we support (Linux, Mac OS)
     runs-on: ${{ matrix.os }}