Revert "Remove our fork of markdown"

This reverts commit d091b771d7adbc7f96faf0ef74dd38f7df29b8ad.

This doesn't fix our rendering problem, so we need to continue to
maintain our fork.

pubspec.lock

@@ -505,12 +505,14 @@ packages:
     source: hosted
     version: "0.11.3+2"
   markdown:
-    dependency: transitive
+    dependency: "direct overridden"
     description:
-      name: markdown
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.7"
+      path: "."
+      ref: HEAD
+      resolved-ref: "2e87055c39b4b29939bb99ceff593880e2bcf20a"
+      url: "https://github.com/GitJournal/markdown.git"
+    source: git
+    version: "2.1.5"
   matcher:
     dependency: transitive
     description:

pubspec.yaml

@@ -72,6 +72,8 @@ dev_dependencies:
 dependency_overrides:
   intl:
     git: https://github.com/GitJournal/intl.git
+  markdown:
+    git: https://github.com/GitJournal/markdown.git
 
 flutter:
   uses-material-design: true