feat: Fixing multiple of; Removing dedicated draft-06 test case

Author: DannyvdSluijs

src/JsonSchema/Constraints/Drafts/Draft06/MaximumConstraint.php

@@ -25,6 +25,10 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
             return;
         }
 
+        if (!is_numeric($value)) {
+            return;
+        }
+
         if ($value <= $schema->maximum) {
             return;
         }

src/JsonSchema/Constraints/Drafts/Draft06/MultipleOfConstraint.php

@@ -29,7 +29,7 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
             return;
         }
 
-        if (fmod($value, $schema->multipleOf) === 0) {
+        if (fmod($value, $schema->multipleOf) === 0.0) {
             return;
         }