fix(docs): use JSX style object

Author: Pyrax

www/src/pages/index.mdx

@@ -5,7 +5,7 @@ import Readme from '../../README.md'
     src='cover.png'
     alt='react-netlify-forms'
     title='react-netlify-forms'
-    style='padding:1rem 0.5rem 0rem 0.5rem; max-height:140px;'
+    style={{ padding: '1rem 0.5rem 0rem 0.5rem', maxHeight: '140px' }}
   />
 </center>