[ArchiMate 3.1] Update link to 3.1 spec docs
<topic href="https://www.archimatetool.com" label="Archi Website">
</topic>
- <topic href="http://pubs.opengroup.org/architecture/archimate3-doc/toc.html" label="ArchiMate 3 Specification">
+ <topic href="http://pubs.opengroup.org/architecture/archimate31-doc/toc.html" label="ArchiMate 3.1 Specification">
</topic>
<topic href="https://masteringarchimate.com/the-book-edition-iii/" label="Mastering ArchiMate Book">
</topic>
