Update MetaGraphs requirement to 0.9.0 in /docs

Updates the requirements on [MetaGraphs](https://github.com/JuliaGraphs/MetaGraphs.jl) to permit the latest version.
- [Release notes](https://github.com/JuliaGraphs/MetaGraphs.jl/releases)
- [Commits](JuliaGraphs/MetaGraphs.jl@v0.5.0...v0.9.0)

---
updated-dependencies:
- dependency-name: MetaGraphs
  dependency-version: 0.9.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

docs/Project.toml

@@ -12,3 +12,4 @@ MetaGraphsNext = "fa8bd995-216d-47f1-8a91-f3b68fbeb377"
 Documenter = "1"
 Graphs = "1.13.3"
 JLD2 = "0.6"
+MetaGraphs = "0.9.0"