CI: Test with PyPy 3.11

Author: dbohdan

.github/workflows/ci.yml

@@ -25,6 +25,7 @@ jobs:
           - "pypy-3.8"
           - "pypy-3.9"
           - "pypy-3.10"
+          - "pypy-3.11"
         lua-version:
           - "bundle"
           - "lua5.3"