Update _config.yml

remove default statement

Author: bitkarrot

_config.yml

@@ -29,7 +29,7 @@ github_username:  chaincodelabs
 
 # Build settings
 theme: just-the-docs
-# Color scheme supports "light" (default) and "dark"
+# Color scheme supports "light" and "dark"
 color_scheme: dark
 plugins:
   - asciidoctor-diagram