Bump addressable from 2.5.0 to 2.8.0 in /uaa/slate (#1603)

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] <support@github.com>

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

uaa/slate/Gemfile.lock

@@ -6,8 +6,8 @@ GEM
       i18n (~> 0.7)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    addressable (2.5.0)
-      public_suffix (~> 2.0, >= 2.0.2)
+    addressable (2.8.0)
+      public_suffix (>= 2.0.2, < 5.0)
     autoprefixer-rails (6.6.1)
       execjs
     backports (3.6.8)
@@ -92,7 +92,7 @@ GEM
     padrino-support (0.13.3.3)
       activesupport (>= 3.1)
     parallel (1.10.0)
-    public_suffix (2.0.5)
+    public_suffix (4.0.6)
     racc (1.5.2)
     rack (2.0.8)
     rb-fsevent (0.9.8)