Bump mdl from 0.12.0 to 0.13.0

Bumps [mdl](https://github.com/mivok/markdownlint) from 0.12.0 to 0.13.0.
- [Changelog](https://github.com/markdownlint/markdownlint/blob/main/CHANGELOG.md)
- [Commits](markdownlint/markdownlint@v0.12.0...v0.13.0)

---
updated-dependencies:
- dependency-name: mdl
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -3,10 +3,10 @@ GEM
   specs:
     addressable (2.8.1)
       public_suffix (>= 2.0.2, < 6.0)
-    chef-utils (18.0.161)
+    chef-utils (18.3.0)
       concurrent-ruby
     colorator (1.1.0)
-    concurrent-ruby (1.2.0)
+    concurrent-ruby (1.2.2)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
@@ -47,7 +47,7 @@ GEM
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
-    mdl (0.12.0)
+    mdl (0.13.0)
       kramdown (~> 2.3)
       kramdown-parser-gfm (~> 1.1)
       mixlib-cli (~> 2.1, >= 2.1.1)
@@ -66,7 +66,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.5)
+    rexml (3.2.6)
     rouge (4.1.0)
     safe_yaml (1.0.5)
     sass-embedded (1.58.0)