Don't get me wrong, I know that my comment sounds a little bit weird in the context of your project. I know that I could just rightclick the file, download and open it in the browser.
It's just more of a hint to you that, whenever you want to show something to the public, every extra action the user has to make, could lose you that user.
Keep in mind that "we" want to figure out in seconds if we want to spend more time looking at what you have created or not.
What I would wish that I could do is just make it so that there was a link to the HTML file in the Readme. Click it and there you go. My impression is that this is discouraged. (Am I wrong about that?)
It's just more of a hint to you that, whenever you want to show something to the public, every extra action the user has to make, could lose you that user.
Keep in mind that "we" want to figure out in seconds if we want to spend more time looking at what you have created or not.