Support the latest pkg:html

pkgs/markdown/pubspec.yaml

diff --git a/pkgs/markdown/pubspec.yaml b/pkgs/markdown/pubspec.yaml
index 05d64c6..670248f 100644
--- a/pkgs/markdown/pubspec.yaml
+++ b/pkgs/markdown/pubspec.yaml
@@ -21,7 +21,7 @@
   build_web_compilers: ^1.0.0
   collection: ^1.2.0
   expected_output: ^1.2.1
-  html: '>=0.12.2 <0.14.0'
+  html: '>=0.12.2 <0.15.0'
   js: ^0.6.1
   path: ^1.3.1
   pedantic: ^1.3.0