Update rubocop-jekyll requirement from ~> 0.13.0 to ~> 0.14.0 (#1037)

Updates the requirements on [rubocop-jekyll](https://github.com/jekyll/rubocop-jekyll) to permit the latest version.
- [Release notes](https://github.com/jekyll/rubocop-jekyll/releases)
- [Changelog](https://github.com/jekyll/rubocop-jekyll/blob/master/History.markdown)
- [Commits](jekyll/rubocop-jekyll@v0.13.0...v0.14.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Kurt Garloff <[email protected]>

Author: dependabot[bot]

_gems/jekyll-seo-tag/jekyll-seo-tag.gemspec

@@ -30,5 +30,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", ">= 1.15"
   spec.add_development_dependency "html-proofer", "~> 5.0"
   spec.add_development_dependency "rspec", "~> 3.5"
-  spec.add_development_dependency "rubocop-jekyll", "~> 0.13.0"
+  spec.add_development_dependency "rubocop-jekyll", "~> 0.14.0"
 end