fixed broken test

        List<String> ping = new ArrayList<>();

        foo.add("Bar");

        ping.add("Pong");

        expectedHeader.put("X-Foo", foo);

        expectedHeader.put("X-Ping", ping);

        // HTTP header names are case-insensitive, according to RFC 2616 -> lowercase!

        // lower case happens in @Headers.toMultiMap()

        expectedHeader.put("x-foo", foo);

        expectedHeader.put("x-ping", ping);

        NextcloudRequest request = new NextcloudRequest.Builder()

                .setMethod("GET")