Update ghcr.io/robert-koch-institut/mex-backend Docker tag to v0.29.0 (…

…#235)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|
[ghcr.io/robert-koch-institut/mex-backend](https://redirect.github.com/robert-koch-institut/mex-backend)
| service | minor | `0.28.0` -> `0.29.0` |

---

### Release Notes

<details>
<summary>robert-koch-institut/mex-backend
(ghcr.io/robert-koch-institut/mex-backend)</summary>

###
[`v0.29.0`](https://redirect.github.com/robert-koch-institut/mex-backend/blob/HEAD/CHANGELOG.md#0290---2025-01-22)

[Compare
Source](https://redirect.github.com/robert-koch-institut/mex-backend/compare/0.28.0...0.29.0)

##### Changes

- add support for full text queries on nested models to find
extracted/rule/merged items
- optimize extracted/rule/merged search queries by applying sorting and
pagination
before pulling in nested models as well as identifiers from referenced
merged items
and by replacing subqueries with cypher "pattern comprehension" syntax
- prefix `components` in merged queries with `_`, to be more harmonious
with `_refs`
- add email fields to `SEARCHABLE_FIELDS` and `SEARCHABLE_CLASSES`
(stop-gap MX-1766)

</details>

---

### Configuration

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Automerge - At any time (no schedule defined).

🚦 **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.

---

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---

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.github/workflows/testing.yml

@@ -35,7 +35,7 @@ jobs:
         ports:
           - 7687:7687
       backend:
-        image: ghcr.io/robert-koch-institut/mex-backend:0.28.0
+        image: ghcr.io/robert-koch-institut/mex-backend:0.29.0
         env:
           MEX_BACKEND_API_USER_DATABASE: ${{ secrets.MEX_BACKEND_API_USER_DATABASE }}
           MEX_BACKEND_API_KEY_DATABASE: ${{ secrets.MEX_BACKEND_API_KEY_DATABASE }}