Bump rocm-docs-core from 1.18.2 to 1.20.0 in /docs/sphinx (#180)

Bumps [rocm-docs-core](https://github.com/ROCm/rocm-docs-core) from 1.18.2 to 1.20.0.
- [Release notes](https://github.com/ROCm/rocm-docs-core/releases)
- [Changelog](https://github.com/ROCm/rocm-docs-core/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/ROCm/rocm-docs-core/compare/v1.18.2...v1.20.0

)

---
updated-dependencies:
- dependency-name: rocm-docs-core
  dependency-version: 1.20.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/sphinx/requirements.in

-rocm-docs-core==1.18.2
+rocm-docs-core==1.20.0

docs/sphinx/requirements.txt

@@ -188,7 +188,7 @@ requests==2.32.2
     # via
     #   pygithub
     #   sphinx
-rocm-docs-core==1.18.2
+rocm-docs-core==1.20.0
     # via -r requirements.in
 rpds-py==0.22.3
     # via