qiime2 plugin does not support RelativeFrequency ?

The help string of `qiime diversity beta-phylogenetic` displays:

```
--i-table ARTIFACT FeatureTable[Frequency | RelativeFrequency | PresenceAbsence]
```

However when passed a `RelativeFrequency` table, we get:

```
Plugin error from diversity:

  Parameter 'table' requires an argument of type FeatureTable[Frequency]. An argument of type FeatureTable[RelativeFrequency] was passed.
```