Update site_url to bitol-io

Author: pflooky

mkdocs.yml

@@ -1,5 +1,5 @@
 site_name: Open Data Contract Standard
-site_url: https://pflooky.github.io/open-data-contract-standard/
+site_url: https://bitol-io.github.io/open-data-contract-standard/
 repo_url: https://github.com/bitol-io/open-data-contract-standard
 repo_name: open-data-contract-standard