Add Grafana Mimir to remote-write integrations (#2125)

Signed-off-by: Richard Hartmann <[email protected]>

Author: RichiH

content/docs/operating/integrations.md

@@ -47,6 +47,7 @@ data volumes.
   * [Gnocchi](https://gnocchi.xyz/prometheus.html): write
   * [Google BigQuery](https://github.com/KohlsTechnology/prometheus_bigquery_remote_storage_adapter): read and write
   * [Google Cloud Spanner](https://github.com/google/truestreet): read and write
+  * [Grafana Mimir](https://github.com/grafana/mimir): read and write
   * [Graphite](https://github.com/prometheus/prometheus/tree/main/documentation/examples/remote_storage/remote_storage_adapter): write
   * [InfluxDB](https://docs.influxdata.com/influxdb/v1.8/supported_protocols/prometheus): read and write
   * [Instana](https://www.instana.com/docs/ecosystem/prometheus/#remote-write): write