Add reasoning for test python versions

Author: jacomago

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"] # testcontainers is not supported on <3.9
     needs: build
     steps:
     - uses: actions/checkout@v4