Use gender values for PROTAGONIST instead of MALE/FEMALE

[alliyya]

For consistency with other tags ex. <GENDEROFAUTHOR/>

<attribute name="GENDEROFAUTHOR">
 <a:documentation xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0" >genderOfAuthor is an optional attribute modifying the element tIntertextuality; therefore, it allows you to identify the sex of the author who wrote the intertext. It will prove useful for researching how women responded to other texts written by male or female authors.</a:documentation>
 <choice>
 <value>WOMAN</value>
 <value>NONCONFORMING</value>
 <value>TRANS</value>
 <value>MAN</value>
 <value>UNKNOWN</value>
 </choice>
 </attribute>