add Python 3.12 to testing

Author: cgcgcg

.github/workflows/build.yml

@@ -19,6 +19,9 @@ jobs:
           - py-version: '3.11'
             c-compiler: 'gcc'
             cxx-compiler: 'g++'
+          - py-version: '3.12'
+            c-compiler: 'gcc'
+            cxx-compiler: 'g++'
           - py-version: '3.10'
             c-compiler: 'clang'
             cxx-compiler: 'clang++'