Bump jekyll-seo-tag from 2.7.1 to 2.8.0 in /docs (#770)

Bumps [jekyll-seo-tag](https://github.com/jekyll/jekyll-seo-tag) from 2.7.1 to 2.8.0.
- [Release notes](https://github.com/jekyll/jekyll-seo-tag/releases)
- [Changelog](https://github.com/jekyll/jekyll-seo-tag/blob/master/History.markdown)
- [Commits](https://github.com/jekyll/jekyll-seo-tag/compare/v2.7.1...v2.8.0)

---
updated-dependencies:
- dependency-name: jekyll-seo-tag
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/Gemfile

@@ -2,5 +2,5 @@ source "https://rubygems.org"
 
 group :jekyll_plugins do
   gem "jekyll", ">= 3.6.3"
-  gem "jekyll-seo-tag", "~> 2.7.1"
+  gem "jekyll-seo-tag", "~> 2.8.0"
 end

docs/Gemfile.lock

@@ -5,14 +5,14 @@ GEM
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
     concurrent-ruby (1.1.9)
-    em-websocket (0.5.2)
+    em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
-      http_parser.rb (~> 0.6.0)
+      http_parser.rb (~> 0)
     eventmachine (1.2.7)
-    ffi (1.15.4)
+    ffi (1.15.5)
     forwardable-extended (2.6.0)
-    http_parser.rb (0.6.0)
-    i18n (1.8.10)
+    http_parser.rb (0.8.0)
+    i18n (1.9.1)
       concurrent-ruby (~> 1.0)
     jekyll (4.2.1)
       addressable (~> 2.4)
@@ -31,7 +31,7 @@ GEM
       terminal-table (~> 2.0)
     jekyll-sass-converter (2.1.0)
       sassc (> 2.0.1, < 3.0)
-    jekyll-seo-tag (2.7.1)
+    jekyll-seo-tag (2.8.0)
       jekyll (>= 3.8, < 5.0)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
@@ -40,18 +40,18 @@ GEM
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.7.0)
+    listen (3.7.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
-    rb-fsevent (0.11.0)
+    rb-fsevent (0.11.1)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     rexml (3.2.5)
-    rouge (3.26.1)
+    rouge (3.28.0)
     safe_yaml (1.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
@@ -65,7 +65,7 @@ PLATFORMS
 
 DEPENDENCIES
   jekyll (>= 3.6.3)
-  jekyll-seo-tag (~> 2.7.1)
+  jekyll-seo-tag (~> 2.8.0)
 
 BUNDLED WITH
    2.2.2