_config.toml: Fix about redirection (#14)

- When clicking on the about logo in the main menu, the site was not redirecting to about page

- This was happening because the about url in the _config.yml was set to '/'

--> Fix that by defining the about page url.

Signed-off-by: prateekpunetha <prateekpunetha@gmail.com>

config.toml

@@ -17,7 +17,7 @@ author = "Harsh Shandilya"
   identifier = "about"
   name = "about"
   title = "About"
-  url = "/"
+  url = "/about"
 
 [[menu.main]]
   identifier = "blog"