docs: fix logo

Author: Yehonal

docs/_config.yml

@@ -28,7 +28,7 @@ show_downloads: true
 # (string) Specify branch rendered by gitpages allowing wiki tool buttons to work
 git_branch: 'gh-pages'
 # (string) Url of logo image, it can be full, absolute or relative.
-logo_url: http://www.drassil.org/nest-yalc/logo-small_yalc.png
+logo_url: assets/images/logo-small_yalc.png
 # (string) The UA-XXXXX-Y code from google analytic to enable GA on your wiki
 google_analytics:
 # (string) folder where wiki pages are stored, it's needed for tool buttons