This requires re-vendoring a bunch of other things (as well as the old
Sirupsen/logrus path), the relevant commits being:
* github.com/xeipuuv/gojsonschema@0c8571ac0ce161a5feb57375a9cdf148c98c0f70
* github.com/xeipuuv/gojsonpointer@6fe8760cad3569743d51ddbb243b26f8456742dc
* github.com/xeipuuv/gojsonreference@e02fc20de94c78484cd5ffb007f8af96be030a45
* go4.org@034d17a462f7b2dcd1a4a73553ec5357ff6e6c6e
Signed-off-by: Aleksa Sarai <asarai@suse.de>