feat(hugo): upgrade Hugo to v0.21 (#19)

README.md

@@ -46,6 +46,7 @@ See the [Hugo Documentation](https://gohugo.io/) for more information.
 
 |  hugo-bin version | Hugo version |
 |:-----------------:|:------------:|
+|       ^0.8.0      |     v0.21    |
 |       ^0.7.0      |     v0.20.7  |
 |       ^0.6.0      |     v0.19    |
 |       ^0.5.0      |     v0.18.1  |

package.json

@@ -1,7 +1,7 @@
 {
   "name": "hugo-bin",
   "version": "0.7.0",
-  "hugoVersion": "0.20.7",
+  "hugoVersion": "0.21",
   "description": "Binary wrapper for Hugo",
   "main": "index.js",
   "scripts": {