Build(deps): Bump rocm-docs-core from 1.7.2 to 1.8.1 in /docs/sphinx (#3741)

Bumps [rocm-docs-core](https://github.com/ROCm/rocm-docs-core) from 1.7.2 to 1.8.1.
- [Release notes](https://github.com/ROCm/rocm-docs-core/releases)
- [Changelog](https://github.com/ROCm/rocm-docs-core/blob/v1.8.1/CHANGELOG.md)
- [Commits](https://github.com/ROCm/rocm-docs-core/compare/v1.7.2...v1.8.1)

---
updated-dependencies:
- dependency-name: rocm-docs-core
  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

@@ -1,2 +1,2 @@
-rocm-docs-core==1.7.2
+rocm-docs-core==1.8.1
 sphinx-reredirects