deps: Update dependency pytz to v2025 (#526)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [pytz](http://pythonhosted.org/pytz) | `==2024.2` -> `==2025.1` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/pytz/2025.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/pypi/pytz/2025.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![passing](https://developer.mend.io/api/mc/badges/compatibility/pypi/pytz/2024.2/2025.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pytz/2024.2/2025.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

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

♻ **Rebasing**: Never, 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 was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/GoogleCloudPlatform/genai-databases-retrieval-app).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOS4xNDUuMCIsInVwZGF0ZWRJblZlciI6IjM5LjE0NS4wIiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6W119-->

Co-authored-by: Yuan <[email protected]>

Author: renovate-bot

llm_demo/requirements.txt

@@ -10,7 +10,7 @@ markdown==3.7
 types-Markdown==3.7.0.20240822
 uvicorn[standard]==0.31.0
 python-multipart==0.0.18
-pytz==2024.2
+pytz==2025.1
 types-pytz==2025.1.0.20250204
 langgraph==0.2.48
 httpx==0.27.2