Add Python 3.12 to CI

Author: argilo

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
     steps:
       - name: Install dependencies
         run: sudo apt-get install -y gcc-avr avr-libc simulavr