Update jekyll-timeago requirement from ~> 0.13.1 to ~> 0.15.0 in /pages

Updates the requirements on [jekyll-timeago](https://github.com/markets/jekyll-timeago) to permit the latest version.
- [Release notes](https://github.com/markets/jekyll-timeago/releases)
- [Commits](markets/jekyll-timeago@v0.13.1...v0.15.0)

---
updated-dependencies:
- dependency-name: jekyll-timeago
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pages/Gemfile

@@ -3,5 +3,5 @@ source 'https://rubygems.org'
 gem 'jekyll', '~> 4.2'
 
 group :jekyll_plugins do
-  gem 'jekyll-timeago', '~> 0.13.1'
+  gem 'jekyll-timeago', '~> 0.15.0'
 end