Replace code.forgejo.org/oci/python Docker tag with data.forgejo.org/oci/python slim (#1497)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| code.forgejo.org/oci/python → data.forgejo.org/oci/python | container | replacement | `slim` → `slim` |

This is a special PR that replaces `code.forgejo.org/oci/python` with the community suggested minimal stable replacement version.

---

### Configuration

📅 **Schedule**: Branch creation - "" (UTC), Automerge - Between 12:00 AM and 03:59 AM ( * 0-3 * * * ) (UTC).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi44NS4zIiwidXBkYXRlZEluVmVyIjoiNDIuODUuMyIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOltdfQ==-->

Reviewed-on: https://code.forgejo.org/forgejo/end-to-end/pulls/1497
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.code.forgejo.org>
Co-authored-by: Renovate Bot <bot@kriese.eu>
Co-committed-by: Renovate Bot <bot@kriese.eu>

actions/example-shell/.forgejo/workflows/test.yml

@@ -47,7 +47,7 @@ jobs:
     needs: [alpine]
     runs-on: docker
     container:
-      image: code.forgejo.org/oci/python:slim
+      image: data.forgejo.org/oci/python:slim
     steps:
       - name: python => python {0}
         shell: python