Add support of TLS 1.3 to Best Practices

After working on my own site trying to not only improve my lighthouse score but to provide a better experience all round, I started to look into my website/pwa security. I had TLS1.2 enabled and had deprecated 1.1, 1.0 and SSL but after a little digging, I realized that I didn't have TLS1.3 support. Given that 1.2 is over 10 years old and 1.3 is now well and truly the future, it would make sense to add it to the Best Practices section of the Lightouse Report.

TY