Merge pull request #617 from ziyafenn/patch-1

Add Astro.

Thanks @ziyafenn !

Author: Phil Hawksworth

src/site/generators/astro.md

@@ -0,0 +1,19 @@
+---
+title: Astro
+repo: snowpackjs/astro
+homepage: https://astro.build
+language:
+  - JavaScript
+license:
+  - MIT
+templates:
+  - Svelte
+  - React
+  - Preact
+  - Vue
+  - HTML
+description: Build faster websites with less client-side Javascript
+---
+Astro is a fresh but familiar approach to building websites. 
+Astro combines decades of proven performance best practices with the DX improvements of the component-oriented era. 
+Use your favorite JavaScript framework and automatically ship the bare-minimum amount of JavaScript—by default.