chore(deps): update dependency structlog to v21.2.0 (GoogleCloudPlatform#6909)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [structlog](https://www.structlog.org/) ([source](https://togithub.com/sponsors/hynek)) | `==21.1.0` -> `==21.2.0` | [![age](https://badges.renovateapi.com/packages/pypi/structlog/21.2.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/pypi/structlog/21.2.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/pypi/structlog/21.2.0/compatibility-slim/21.1.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/pypi/structlog/21.2.0/confidence-slim/21.1.0)](https://docs.renovatebot.com/merge-confidence/) |

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run/idp-sql/requirements.txt

@@ -3,4 +3,4 @@ SQLAlchemy==1.4.22
 pg8000==1.21.3
 gunicorn==20.1.0
 firebase-admin==5.0.3
-structlog==21.1.0
+structlog==21.2.0