fix broken link (#3559)

Refs: https://app.intercom.com/a/apps/qiqpfgjg/inbox/inbox/5079389/conversations/26852700007188
Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

website/src/docs/companion.md

@@ -263,7 +263,7 @@ export COMPANION_PERIODIC_PING_INTERVAL=60000
 export COMPANION_PERIODIC_PING_STATIC_JSON_PAYLOAD="{\"static\":\"data\"}"
 ```
 
-See [env.example.sh](https://github.com/transloadit/uppy/blob/main/env.example.sh) for an example configuration script.
+See [`.env.example`](https://github.com/transloadit/uppy/blob/main/.env.example) for an example environment configuration file.
 
 ### Options
 

website/themes/uppy/layout/partials/docs_menu.ejs

@@ -12,7 +12,7 @@
       { category: 'Community Projects', path: 'docs/community-projects/', link: true },
       { category: 'React', path: 'docs/react/', link: true },
       { category: 'Other Integrations', path: 'docs/vue/', link: true },
-      { category: 'Contributing', path: 'docs/contributing/', link: true },
+      { category: 'Contributing', path: 'docs/contributing.html', link: true },
     ]
   } else if (page.type === 'examples') {
     categories = [