chore: update readme

Author: evenstensberg

README.md

@@ -1,7 +1,7 @@
 <div align="center">
-    <a href="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/webpack/sass-loader">
-        <img width="200" height="200" src="https://webpack.js.org/assets/icon-square-big.svg">
-    </a>
+  <a href="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/webpack/sass-loader">
+    <img width="200" height="200" src="https://webpack.js.org/assets/icon-square-big.svg">
+  </a>
 </div>
 
 [![npm][npm]][npm-url]