doc: fix url of Ganzetti et al. 2016
doc: fix url of Ganzetti et al. 2016

Credit for catching it should go to Prof. Simon Warfield, thanks much for reporting!
oesteban/mriqc,poldracklab/mriqc,oesteban/mriqc,poldracklab/mriqc,poldracklab/mriqc,oesteban/mriqc,oesteban/mriqc,poldracklab/mriqc