Bump libs/json from 8c391e0 to 960b763 (#747)

Bumps [libs/json](https://github.com/nlohmann/json) from `8c391e0` to `960b763`.
- [Release notes](https://github.com/nlohmann/json/releases)
- [Commits](nlohmann/json@8c391e0...960b763)

---
updated-dependencies:
- dependency-name: libs/json
  dependency-type: direct:production
...

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