Pin to a specific version of html-proofer

Author: PeterJCLaw

Gemfile

@@ -10,7 +10,7 @@ gem 'jekyll', 3.9
 gem 'jekyll-redirect-from'
 
 # For testing output
-gem 'html-proofer'
+gem 'html-proofer', '~> 4'
 
 # Avoid polling on windows
 gem 'wdm', '>= 0.1.0'

Gemfile.lock

@@ -97,7 +97,7 @@ PLATFORMS
   x64-mingw32
 
 DEPENDENCIES
-  html-proofer
+  html-proofer (~> 4)
   jekyll (= 3.9)
   jekyll-redirect-from
   kramdown