Update Aggregator documentation

Author: jpraynaud

docs/root/manual/developer-docs/nodes/mithril-aggregator.md

@@ -299,6 +299,7 @@ General parameters:
 | `snapshot_directory` | `--snapshot-directory` | - | `SNAPSHOT_DIRECTORY` | Directory to store local snapshots of the **Cardano Node** | `.` | - | :heavy_check_mark: |
 | `snapshot_store_type` | - | - | `SNAPSHOT_STORE_TYPE` | Type of snapshot store to use | - | `gcp` or `local` | :heavy_check_mark: |
 | `snapshot_uploader_type` | - | - | `SNAPSHOT_UPLOADER_TYPE` | Type of snapshot uploader to use | - | `gcp` or `local` | :heavy_check_mark: |
+| `snapshot_bucket_name` | - | - | `SNAPSHOT_BUCKET_NAME` | Name of the bucket where the snapshots are stored  | - | `snapshot-bucket` | :heavy_check_mark: | Required if `snapshot_uploader_type` is `gcp`
 | `run_interval` | - | - | `RUN_INTERVAL` | Interval between two runtime cycles in ms | - | `60000` | :heavy_check_mark: |
 | `url_snapshot_manifest` | - | - | `URL_SNAPSHOT_MANIFEST` | Snapshots manifest location | - | Only if `snapshot_store_type` is `gcp`, else it should be `` | :heavy_check_mark: |