Update the browser share graphic for 2020.

[prestoncarman]

Currently the "Desktop browser market share July 2017" figure from the Web Standard section is a few years old. It would be nice to have a more current graphic.

[kootsoop]

This is where the picture is: https://info340.github.io/standards-and-accessibility.html#web-standards

Current data is here: https://www.netmarketshare.com/browser-market-share.aspx?options=%7B%22filter%22%3A%7B%22%24and%22%3A%5B%7B%22deviceType%22%3A%7B%22%24in%22%3A%5B%22Desktop%2Flaptop%22%5D%7D%7D%5D%7D%2C%22dateLabel%22%3A%22Custom%22%2C%22attributes%22%3A%22share%22%2C%22group%22%3A%22browser%22%2C%22sort%22%3A%7B%22share%22%3A-1%7D%2C%22id%22%3A%22browsersDesktop%22%2C%22dateInterval%22%3A%22Monthly%22%2C%22dateStart%22%3A%222023-01%22%2C%22dateEnd%22%3A%222023-07%22%2C%22pageLength%22%3A100%2C%22segments%22%3A%22-1000%22%7D

I'll try to put in a pull request later...