Update apa.csl

[dazza-codes]

The fixture data for apa.csl was last updated 4 years ago. Is it time to pull in an update from
https://github.com/citation-style-language/styles/blob/master/apa.csl

[inukshuk]

This is just a fixture we use to test an arbitrary but realistic style. The style itself is of little consequence here. You can install more recent styles using the 'csl-styles' gem or you can just download the styles you need (just point CSL::Style.root to the directory and you can load any style with just its name using CSL::Style.load).