Bump addressable from 2.5.0 to 2.8.0 in /examples/custom

Bumps [addressable](https://github.com/sporkmonger/addressable) from 2.5.0 to 2.8.0.
- [Release notes](https://github.com/sporkmonger/addressable/releases)
- [Changelog](https://github.com/sporkmonger/addressable/blob/main/CHANGELOG.md)
- [Commits](sporkmonger/addressable@addressable-2.5.0...addressable-2.8.0)

---
updated-dependencies:
- dependency-name: addressable
  dependency-type: indirect
...

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

examples/custom/Gemfile.lock

@@ -1,8 +1,8 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.0)
-      public_suffix (~> 2.0, >= 2.0.2)
+    addressable (2.8.0)
+      public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
     ffi (1.9.17)
     forwardable-extended (2.6.0)
@@ -19,6 +19,8 @@ GEM
       safe_yaml (~> 1.0)
     jekyll-feed (0.8.0)
       jekyll (~> 3.3)
+    jekyll-html5-youtube (0.0.5)
+      jekyll (~> 3.4)
     jekyll-sass-converter (1.5.0)
       sass (~> 3.4)
     jekyll-watch (1.5.0)
@@ -33,7 +35,7 @@ GEM
       jekyll (~> 3.3)
     pathutil (0.14.0)
       forwardable-extended (~> 2.6)
-    public_suffix (2.0.5)
+    public_suffix (4.0.6)
     rb-fsevent (0.9.8)
     rb-inotify (0.9.8)
       ffi (>= 0.5.0)
@@ -47,6 +49,7 @@ PLATFORMS
 DEPENDENCIES
   jekyll (= 3.4.0)
   jekyll-feed (~> 0.6)
+  jekyll-html5-youtube (~> 0.0.5)
   minima (~> 2.0)
   tzinfo-data