Bump diff and @eventcatalog/core in /src/eventcatalog

Bumps [diff](https://github.com/kpdecker/jsdiff) to 8.0.3 and updates ancestor dependency [@eventcatalog/core](https://github.com/event-catalog/eventcatalog). These dependencies need to be updated together.


Updates `diff` from 7.0.0 to 8.0.3
- [Changelog](https://github.com/kpdecker/jsdiff/blob/master/release-notes.md)
- [Commits](kpdecker/jsdiff@7.0.0...v8.0.3)

Updates `@eventcatalog/core` from 2.64.3 to 3.16.0
- [Release notes](https://github.com/event-catalog/eventcatalog/releases)
- [Commits](https://github.com/event-catalog/eventcatalog/compare/v2.64.3...@eventcatalog/core@3.16.0)

---
updated-dependencies:
- dependency-name: diff
  dependency-version: 8.0.3
  dependency-type: indirect
- dependency-name: "@eventcatalog/core"
  dependency-version: 3.16.0
  dependency-type: direct:production
...

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Author: dependabot[bot]