fix: docs/Gemfile & docs/Gemfile.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-FARADAY-15253521

Author: snyk-bot

docs/Gemfile

@@ -15,7 +15,7 @@ gem "minima", "~> 2.0"
 
 # If you want to use GitHub Pages, remove the "gem "jekyll"" above and
 # uncomment the line below. To upgrade, run `bundle update github-pages`.
-# gem "github-pages", group: :jekyll_plugins
+# gem "github-pages", ">= 203", group: :jekyll_plugins
 
 # If you have any plugins, put them here!
 group :jekyll_plugins do