Bump orjson from 3.8.9 to 3.9.15

Bumps [orjson](https://github.com/ijl/orjson) from 3.8.9 to 3.9.15.
- [Release notes](https://github.com/ijl/orjson/releases)
- [Changelog](https://github.com/ijl/orjson/blob/master/CHANGELOG.md)
- [Commits](ijl/orjson@3.8.9...3.9.15)

---
updated-dependencies:
- dependency-name: orjson
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -16,7 +16,7 @@ idna==3.4
 itsdangerous==2.1.2
 Jinja2==3.1.3
 MarkupSafe==2.1.2
-orjson==3.8.9
+orjson==3.9.15
 psycopg2-binary==2.9.6
 pydantic==1.10.7
 python-dotenv==1.0.0