[ADDENDUM][ISSUE-4] Include the OPTIONS method validation

Author: alexpopero

src/lua/api-gateway/validation/factory.lua

@@ -53,7 +53,7 @@ end
 -- It calls an internal /validate-request path which can provide any custom implementation for request validation
 local function _validateRequest()
     if (ngx.var.request_method == 'OPTIONS') then
-        return ngx.exit(ngx.OK);
+        return ngx.OK;
     end
 
     local res = ngx.location.capture("/validate-request", { share_all_vars = true });