Update lib/HTTP.php

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Sebastian Sterk <7263970+sebastiansterk@users.noreply.github.com>

Author: sebastiansterk

lib/HTTP.php

@@ -56,10 +56,13 @@ public function sendUserData($user, $password) {
 			$client = $this->httpClientService->newClient();
 
 			$response = $client->post($this->authenticationEndpoint, [
-				'form_params' => [
+				'body' => json_encode([
 					'accessKey' => $this->accessKey,
 					'user' => $user,
 					'password' => $password
+				]),
+				'headers' => [
+					'Content-Type' => 'application/json'
 				],
 				'timeout' => 10,
 			]);