Bump pydantic-core from 2.6.3 to 2.18.3

Bumps [pydantic-core](https://github.com/pydantic/pydantic-core) from 2.6.3 to 2.18.3.
- [Release notes](https://github.com/pydantic/pydantic-core/releases)
- [Commits](pydantic/pydantic-core@v2.6.3...v2.18.3)

---
updated-dependencies:
- dependency-name: pydantic-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -7,7 +7,7 @@ idna==3.4
 isodate==0.6.1
 lxml==4.9.3
 pydantic==2.3.0
-pydantic_core==2.6.3
+pydantic_core==2.18.3
 pyparsing==3.1.1
 rdflib==7.0.0
 six==1.16.0