added swaggest php implementation and benchmark

_data/validator-libraries.yml

@@ -229,6 +229,11 @@
       notes: 
       draft: [6, 7]
       license: "Apache License 2.0"
+    - name: Swaggest Json Schema
+      url: https://github.com/swaggest/php-json-schema
+      notes:
+      draft: [4, 6, 7]
+      license: "MIT"
 - name: Perl
   implementations:
     - name: JSV::Validator

implementations.md

@@ -83,6 +83,9 @@ Validation benchmarks
     -   [z-schema validator benchmark](https://github.com/zaggino/z-schema#benchmarks) - compares performance in the individual tests from JSON-Schema Test Suite (MIT)
     -   [JSCK validator benchmark](https://github.com/pandastrike/jsck#benchmarks) - shows performance for JSON-schemas of different complexity (MIT)
 
+-   PHP
+    -   [php-json-schema-bench](https://github.com/swaggest/php-json-schema-bench) - comparative benchmark for JSON-schema PHP validators using JSON-Schema Test Suite and z-schema/JSCK (MIT)
+
 Schema generation
 -----------------