Fix mixed content warning when using Chromecast

Tags: #<Tag:0x00007f7397a59cd8>

Chromecast integration (Cast) returns image url starting with “http://” which creates mixed content wornings in modern browsers:

" 1. Mixed content: load all resources via HTTPS to improve the security of your site

  1. Even though the initial HTML page is loaded over a secure HTTPS connection, some resources like images, stylesheets or scripts are being accessed over an insecure HTTP connection. Usage of insecure resources is restricted to strengthen the security of your entire site.

To resolve this issue load all resources over a secure HTTPS connection."

We can easely change adress to “https://” prefix and it will continue to work:
In:
homeassistant/components/cast/media_player.py
Function:
def media_image_url(self):
Row 607:
code can be changed from:
return images[0].url if images and images[0].url else None
to
return images[0].replace(“http://”,“https://”).url if images and images[0].url else None

This seems more like an issue / PR than a feature request.