Using pypy3.12 instead of pypy3.8 for GitHub actions

Author: leszekhanusz

.github/workflows/tests.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "pypy3.8"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "pypy3.12"]
         os: [ubuntu-24.04, windows-latest]
         exclude:
           - os: windows-latest
@@ -20,7 +20,7 @@ jobs:
           - os: windows-latest
             python-version: "3.12"
           - os: windows-latest
-            python-version: "pypy3.8"
+            python-version: "pypy3.12"
 
     steps:
       - uses: actions/checkout@v4