add 3.12 to build-test.yml (#454)

Author: emlowe

.github/workflows/build-test.yaml

@@ -48,7 +48,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-latest, ubuntu-latest, windows-latest]
-        python: ['3.8', '3.9', '3.10', '3.11']
+        python: ['3.8', '3.9', '3.10', '3.11', '3.12']
 
     steps:
     - name: Checkout code