Merge "Upgrade justinrainbow/json-schema to ~3.0"

diff --cc composer.json
index 956739d,c8ed37e..2243b7c
--- 1/composer.json
--- 2/composer.json
+++ b/composer.json
@@@ -45,10 -45,10 +45,10 @@@
        },
        "require-dev": {
                "jakub-onderka/php-parallel-lint": "0.9.2",
-               "justinrainbow/json-schema": "~1.6",
+               "justinrainbow/json-schema": "~3.0",
                "mediawiki/mediawiki-codesniffer": "0.7.2",
                "monolog/monolog": "~1.18.2",
 -              "nikic/php-parser": "1.4.1",
 +              "nikic/php-parser": "2.1.0",
                "nmred/kafka-php": "0.1.5",
                "phpunit/phpunit": "4.8.24",
                "wikimedia/avro": "1.7.7"