fix BIDS-validator link

Author: surchs

docs/usage.rst

@@ -18,7 +18,7 @@ The input dataset is required to be in valid :abbr:`BIDS (Brain Imaging Data
 Structure)` format, and it must include at least one T1w structural image and
 (unless disabled with a flag) a BOLD series.
 We highly recommend that you validate your dataset with the free, online
-`BIDS Validator <http://incf.github.io/bids-validator/>`_.
+`BIDS Validator <http://bids-standard.github.io/bids-validator/>`_.
 
 The exact command to run ``fmriprep`` depends on the Installation_ method.
 The common parts of the command follow the `BIDS-Apps