Bump html-proofer from 3.15.2 to 3.15.3

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.15.2 to 3.15.3.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Commits](gjtorikian/html-proofer@v3.15.2...v3.15.3)

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

Author: dependabot-preview[bot]

Gemfile.lock

@@ -83,7 +83,7 @@ GEM
     html-pipeline (2.12.3)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    html-proofer (3.15.2)
+    html-proofer (3.15.3)
       addressable (~> 2.3)
       mercenary (~> 0.3)
       nokogumbo (~> 2.0)