Add new contact filters for email and name

It should be possible to filter by email address or / and name as
described in the API.

References:

- https://developers.lexoffice.io/docs/#contacts-endpoint-purpose

README.md

@@ -63,6 +63,8 @@ $client = $api->contact();
 
 // filters
 $client->size = 100;
+$client->email = '[email protected]';
+$client->name = 'John Doe';
 $client->number = 123456;
 $client->customer = true;
 $client->vendor = false;
@@ -279,4 +281,4 @@ $response = $client->getPage(0);
 // can be possible null because the response body can be empty
 $json = \Sysix\LexOffice\Utils::getJsonFromResponse($response); // as object
 $json = \Sysix\LexOffice\Utils::getJsonFromResponse($response, true); // as associative array
-```
+```

src/Clients/Contact.php

@@ -17,6 +17,10 @@ class Contact extends PaginationClient
 
     protected string $resource = 'contacts';
 
+    public ?string $email = null;
+
+    public ?string $name = null;
+
     public ?int $number = null;
 
     public ?bool $customer = null;
@@ -25,6 +29,8 @@ class Contact extends PaginationClient
 
     protected function buildQueryParams(array $params): string
     {
+        $params['email'] = $this->email;
+        $params['name'] = $this->name;
         $params['number'] = $this->number;
         $params['customer'] = $this->customer;
         $params['vendor'] = $this->vendor;