Add basic Authorization in Matlab script

I try to realize a PUT api in matlab. I have allready this part which is working:

s.id = "e37b35dd-4aca-4ecb-8972-55c3a27a8b11";

data = jsonencode(s,PrettyPrint=true)
% data = jsondecode(s,Prettyprint=true);
body = matlab.net.http.MessageBody(data);

% authorizationField = matlab.net.http.field.AuthorizationField(username,password)
contentTypeField = matlab.net.http.field.ContentTypeField('application/json');

header = [contentTypeField]

method = matlab.net.http.RequestMethod.PUT;
uri = "https://apps.reeleezee.nl/api/v1/4a2dfa57-ff9a-400b-9c3a-b6a3beafd597/salesinvoices/fa19e531-ca5f-4682-b62a-f95d80175440"

request = matlab.net.http.RequestMessage(method,header,body);
show(request)

resp = send(request,uri)

But now i need to add mu authorization. This is a basic authorization (username and password). How can i put this in the header from the script above?