chore: Bump pypy test version to 3.9

Author: jonathanedey

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.8', '3.9', '3.10', '3.11', '3.12', 'pypy3.8']
+        python: ['3.8', '3.9', '3.10', '3.11', '3.12', 'pypy3.9']
 
     steps:
     - uses: actions/checkout@v4