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](https://github.com/mivok/markdownlint/compare/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] <support@github.com>

Gemfile.lock

@@ -158,7 +158,7 @@ GEM
     caxlsx_rails (0.6.3)
       actionpack (>= 3.1)
       caxlsx (>= 3.0)
-    chef-utils (18.2.7)
+    chef-utils (18.4.2)
       concurrent-ruby
     chronic (0.10.2)
     ckeditor (4.3.0)
@@ -334,7 +334,7 @@ GEM
       net-smtp
     marcel (1.0.2)
     matrix (0.4.2)
-    mdl (0.12.0)
+    mdl (0.13.0)
       kramdown (~> 2.3)
       kramdown-parser-gfm (~> 1.1)
       mixlib-cli (~> 2.1, >= 2.1.1)
@@ -740,7 +740,7 @@ DEPENDENCIES
   knapsack_pro (~> 5.7.0)
   launchy (~> 2.5.2)
   letter_opener_web (~> 2.0.0)
-  mdl (~> 0.12.0)
+  mdl (~> 0.13.0)
   mini_magick (~> 4.12.0)
   omniauth (~> 2.1.1)
   omniauth-facebook (~> 9.0.0)