Add PyPy3.12 to CI

Author: hugovk

.github/workflows/build.yml

@@ -47,6 +47,7 @@ jobs:
           - "pypy3.9"
           - "pypy3.10"
           - "pypy3.11"
+          - "pypy3.12"
 
           # Old PyPy versions
           # See https://github.com/pypy/pypy/issues/3990