Replace logo in readme with SVG version
<p align="center">
- <img src="https://user-images.githubusercontent.com/1711539/72443316-5a79f280-37ae-11ea-858f-035209ece2dd.png" alt="rust-analyzer logo">
+ <img
+ src="https://raw.githubusercontent.com/rust-analyzer/rust-analyzer/master/assets/logo-wide.svg"
+ alt="rust-analyzer logo">
</p>
rust-analyzer is an **experimental** modular compiler frontend for the Rust language.
