Docs: MemGraph integration (#541)

Author: gitbuda

README.md

@@ -535,6 +535,7 @@ index = Index(ndim=ndim, metric=CompiledMetric(
 - [x] GPTCache: [Python](https://github.com/zilliztech/GPTCache/releases/tag/0.1.29).
 - [x] Sentence-Transformers: Python [docs](https://www.sbert.net/docs/package_reference/quantization.html#sentence_transformers.quantization.semantic_search_usearch).
 - [x] Pathway: [Rust](https://github.com/pathwaycom/pathway).
+- [x] Memgraph: [C++ MVP](https://github.com/memgraph/memgraph/pull/2406), [C++ Stable](https://github.com/memgraph/memgraph/pull/2500), [docs](https://memgraph.com/docs/querying/vector-search)
 
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