docs: add community implementations of Remote Cache (#9631)

### Description

Adding a few community implementations of the Remote Cache to
self-hosting docs.

If there are others that should be on this list, please open a PR!

docs/repo-docs/core-concepts/remote-caching.mdx

@@ -193,3 +193,10 @@ turbo run build --api="https://my-server.example.com" --token="xxxxxxxxxxxxxxxxx
 Alternatively, [the `TURBO_API` and `TURBO_TOKEN` System Environment Variables](/repo/docs/reference/system-environment-variables) can be used to set the respective values for the Remote Cache once you've logged in.
 
 You can [find the OpenAPI specification for the API here](/api/remote-cache-spec). At this time, all versions of `turbo` are compatible with the `v8` endpoints.
+
+#### Community implementations
+
+The Turborepo community has created open-source implementations of the Remote Cache.
+
+- [`ducktors/turborepo-remote-cache`](https://github.com/ducktors/turborepo-remote-cache)
+- [`Tapico/tapico-turborepo-remote-cache`](https://github.com/Tapico/tapico-turborepo-remote-cache)