README.md: add troubleshooting session for hugo

In case users run hugo (non extension version) we should
have a quick link for helping new developers/users to solve
the website build issue.

Signed-off-by: Douglas Schilling Landgraf <[email protected]>

Author: dougsland

README.md

@@ -58,6 +58,11 @@ make serve
 
 This will start the local Hugo server on port 1313. Open up your browser to http://localhost:1313 to view the website. As you make changes to the source files, Hugo updates the website and forces a browser refresh.
 
+## Troubleshooting
+### error: failed to transform resource: TOCSS: failed to transform "scss/main.scss" (text/x-scss): this feature is not available in your current Hugo version
+
+Hugo is shipped in two set of binaries for technical reasons. The current website runs based on the **Hugo Extended** version only. In the [release page](https://github.com/gohugoio/hugo/releases) look for archives with `extended` in the name. To confirm, run `hugo version` and look for the word `extended`.
+
 ### Troubleshooting macOS for too many open files
 
 If you run `make serve` on macOS and receive the following error: