Hello! I was recently having trouble with this same problem so now anyone now, or in the future can do it!
How to
●First, open the makecode projwct you owuld like to upload
●Next press the share button, (ussually on the top right of your screen
Press share project
●Now press the </> button and choose simulator, copy the code
●go to a text file generator or make a text file if you know how and paste the code you have copied
●finally go to itch.io log into your accout (or make one) press your profile (again usually in the top right) and press “posts” then press projects and press create new project, choose html file and import your text file you have created fill in other details, then press publish and veiw page!
-blobdev out 