remove unsupported PyPy versions

Author: graingert

.github/workflows/main.yaml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9, '3.10', 3.11, 3.12, 3.13, pypy-3.8, pypy-3.9, pypy-3.10]
+        python-version: [3.8, 3.9, '3.10', 3.11, 3.12, 3.13, pypy-3.10]
         os: [macOS-latest, ubuntu-latest, windows-latest]
 
     steps: