fix: enable python3.9 wheels (#60)

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

.github/workflows/wheels.yml

@@ -14,7 +14,7 @@ jobs:
       # list of github vm: https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories
       fail-fast: false
       matrix:
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
         os:
           - name: "ubuntu-latest"