Fix toml formatting in README (#92)

Fix formatting

Author: Ryan Bell

README.md

@@ -40,7 +40,7 @@ Read more about [UI-based plugin installation](https://docs.netlify.com/configur
 
     ```toml
     [build]
-      command   = "npm run build"
+      command = "npm run build"
       publish = "out"
 
     [[plugins]]