ci: add checkout before setting up python (#3297)

* build: Set up Python 3.12 and Poetry caching in docker workflow.

* build: checkout repository before setting up Python 3.12 and Poetry.

.github/workflows/docker-build.yml

@@ -40,6 +40,7 @@ jobs:
     outputs:
       version: ${{ steps.get-version-input.outputs.version || steps.get-version-base.outputs.version || steps.get-version-main.outputs.version }}
     steps:
+      - uses: actions/checkout@v4
       - name: Set up Python 3.12 + Poetry ${{ env.POETRY_VERSION }}
         uses: "./.github/actions/poetry_caching"
         with: