Rollup merge of rust-lang#82313 - jsha:update-normalize-css, r=GuillaumeGomez

Update normalize.css to 8.0.1

From From https://github.com/necolas/normalize.css/releases/tag/8.0.1.

The old version was 3.0.0, from 2014. The new version is from 2018.

I noticed when looking at frontend performance for rustdoc that this file was out of date. The URL in the 3.0.0 license header now resolves to an incorrect destination. And generally it seems good to be up-to-date.

Before-and-after images, plus diff, under details. TL;DR: Nothing changes except a slight adjustment to line height.

<details>

![with-normalize-8 0 1](https://user-images.githubusercontent.com/220205/108581849-bd5c8800-72e4-11eb-9150-78c8d67ca37a.png)

![with-normalize-3 0 0](https://user-images.githubusercontent.com/220205/108581848-bcc3f180-72e4-11eb-8b45-0cd1415a51e5.png)

![diff](https://user-images.githubusercontent.com/220205/108581890-dfeea100-72e4-11eb-93c5-6284492f54a9.png)

</details>

Author: Dylan-DPC