Bump orjson from 3.8.7 to 3.9.15

Bumps [orjson](https://github.com/ijl/orjson) from 3.8.7 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@3.8.7...3.9.15)

---
updated-dependencies:
- dependency-name: orjson
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -99,7 +99,7 @@ myst-parser==0.17.2
     #   sphinxcontrib-opendataservices-jsonschema
 numpy==1.24.2
     # via pandas
-orjson==3.8.7
+orjson==3.9.15
     # via flatterer
 packaging==23.0
     # via sphinx