Remove py38 leftover from ci

Author: xrmx

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [py38, py39, py310, py311, py312, py313]
+        python-version: [py39, py310, py311, py312, py313]
         openai-version: [baseline, latest]
     steps:
     - uses: actions/checkout@v4