Bump haml_lint

Gemfile

@@ -245,7 +245,7 @@ group :development do
 
   # Linters
   gem "rubocop",        "0.47.1"
-  gem "haml_lint",      "0.18.2"
+  gem "haml_lint",      "0.21.0"
   gem "pronto",         "0.8.2"
   gem "pronto-eslint",  "0.8.0"
   gem "pronto-rubocop", "0.8.0"

Gemfile.lock

@@ -277,10 +277,10 @@ GEM
       rubocop (~> 0.20)
     haml (4.0.7)
       tilt
-    haml_lint (0.18.2)
+    haml_lint (0.21.0)
       haml (~> 4.0)
-      rake (>= 10, < 12)
-      rubocop (>= 0.36.0)
+      rake (>= 10, < 13)
+      rubocop (>= 0.47.0)
       sysexits (~> 1.1)
     hamlit (2.8.0)
       temple (>= 0.8.0)
@@ -595,7 +595,7 @@ GEM
       thor (>= 0.18.1, < 2.0)
     rainbow (2.2.1)
     raindrops (0.17.0)
-    rake (11.3.0)
+    rake (12.0.0)
     rb-fsevent (0.9.8)
     rb-inotify (0.9.8)
       ffi (>= 0.5.0)
@@ -825,7 +825,7 @@ DEPENDENCIES
   guard-cucumber (= 2.1.2)
   guard-rspec (= 4.7.3)
   guard-rubocop (= 1.2.0)
-  haml_lint (= 0.18.2)
+  haml_lint (= 0.21.0)
   hamlit (= 2.8.0)
   handlebars_assets (= 0.23.1)
   http_accept_language (= 2.1.0)