Add definition for isoparatype.

[MattBlissett]

Update: just add isoparatype, and await advice from a taxonomic expert for the rest (see #60).

~Two type status terms (hypotype, plesiotype) are present in the GBIF API, but not in the vocabulary. They were added to the API after this discussion.~

Another term, isoparatype, is requested to be added by ALA.

This PR will add ~the three~ a single terms with these definitions:

~Hypotype: A specimen that was not part of the original type series of the species, but is known from a published description, figure, or listing. [Zoo.]~

Isoparatype: A duplicate of a paratype, compare paratype. [Bot.]

~Plesiotype: A specimen upon which a subsequent or additional description or illustration of a previously named species is based. [Zoo.]~

See also https://github.com/CatalogueOfLife/backend/issues/949 . I'll wait for advice from the Catalogue of Life taxonomy group (or other appropriate experts) before merging this; it's difficult to find good definitions for these terms.

https://species-id.net/zooterms/hypotype, https://species-id.net/zooterms/plesiotype and http://www.insdc.org/controlled-vocabulary-typematerial-qualifer are the sources.

[MattBlissett]

diff vocabulary/gbif/type_status.xml vocabulary/gbif/type_status_2021-01-18.xml --ignore-all-space
5c5
<       dc:description="A vocabulary to be used for a nomenclatural type status of a specimen or name. See also the related type reason vocabulary."
---
>       dc:description="A vocabulary to be used for a nomenclatural type status of a specimen or name. See also the related type reason vocabulary. This release adds isoparatype."
7c7
<   dc:issued="2015-02-13"
---
>   dc:issued="2021-01-18"
208a209,219
>  <concept dc:identifier="isoparatype" dc:URI="http://rs.gbif.org/vocabulary/gbif/type_status/isoparatype"
>   dc:relation="http://rs.gbif.org/vocabulary/gbif/type_status/isoparatype"
>   dc:description="A duplicate of a paratype, compare paratype. [Bot.]">
>   <preferred>
>    <term dc:title="isoparatype" xml:lang="en"/>
>   </preferred>
>   <alternative>
>
>   </alternative>
>  </concept>
>