Bump markdown to 2.0.3

Change-Id: Ia67e81b3b18ee6de560acf518059849e1953f6f9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/99541
Reviewed-by: Kevin Moore <kevmoo@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>
diff --git a/DEPS b/DEPS
index fe36b90..0ad497f 100644
--- a/DEPS
+++ b/DEPS
@@ -98,7 +98,7 @@
   "linter_tag": "0.1.86",
   "logging_tag": "0.11.3+2",
   "markupsafe_rev": "8f45f5cfa0009d2a70589bcda0349b8cb2b72783",
-  "markdown_tag": "2.0.2",
+  "markdown_tag": "2.0.3",
   "matcher_tag": "0.12.3",
   "mime_tag": "0.9.6+2",
   "mockito_tag": "d39ac507483b9891165e422ec98d9fb480037c8b",