Add unit of measurement 'rpm' to device class ('frequency')

Okay, I use HA in a boat truly extensively. An ESP32 measures the rpm of the engine. I is UoM ‘rpm’ and get an error:
Entity sensor.esphome_web_052530_rev_counter (<class ‘homeassistant.components.esphome.sensor.EsphomeSensor’>) is using native unit of measurement ‘rpm’ which is not a valid unit for the device class (‘frequency’) it is using; expected one of [‘Hz’, ‘GHz’, ‘MHz’, ‘kHz’]; Please update your configuration if your entity is manually configured, otherwise create a bug report.

So … please add ‘rppm’ as a unit of measurement for device class ‘frequency’.

Technically this is a “rotational_frequency”.