Add stop_id to telemetry payload

Author: avatarneil

agency/README.md

@@ -231,6 +231,7 @@ A standard point of vehicle telemetry. References to latitude and longitude impl
 | `gps.hdop`     | Float          | Required if Available | Horizontal GPS or GNSS accuracy value (see [hdop][hdop]) |
 | `gps.satellites` | Integer      | Required if Available | Number of GPS or GNSS satellites
 | `charge`       | Float          | Required if Applicable | Percent battery charge of vehicle, expressed between 0 and 1 |
+| `stop_id`      | UUID           | Required if Applicable | Stop that the vehicle is currently located at. Only applicable for _docked_ Micromobility. See [Stops](#stops) |
 
 ## Stops