update CI workflow to use Python 3.8.12

Author: OriHoch

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     steps:
     - uses: actions/setup-python@v5
       with:
-        python-version: '3.8.10'
+        python-version: '3.8.12'
     - env:
         DOCKER_APP_IMAGE_NAME: "ghcr.io/hasadna/knesset-data-pipelines/knesset-data-pipelines-airflow"
         DOCKER_LEGACY_IMAGE_NAME: "ghcr.io/hasadna/knesset-data-pipelines/knesset-data-pipelines-legacy"