Bump flutter_markdown from 0.6.19 to 0.6.20+1

Bumps [flutter_markdown](https://github.com/flutter/packages/tree/main/packages) from 0.6.19 to 0.6.20+1.
- [Release notes](https://github.com/flutter/packages/releases)
- [Commits](https://github.com/flutter/packages/commits/flutter_markdown-v0.6.20/packages)

---
updated-dependencies:
- dependency-name: flutter_markdown
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

pubspec.lock

@@ -258,10 +258,10 @@ packages:
     dependency: "direct main"
     description:
       name: flutter_markdown
-      sha256: "21b085a1c185e46701373866144ced56cfb7a0c33f63c916bb8fe2d0c1491278"
+      sha256: a64c5323ac83ed2b7940d2b6288d160aa1753ff271ba9d9b2a86770414aa3eab
       url: "https://pub.dev"
     source: hosted
-    version: "0.6.19"
+    version: "0.6.20+1"
   flutter_plugin_android_lifecycle:
     dependency: transitive
     description:

pubspec.yaml

@@ -20,7 +20,7 @@ dependencies:
   flutter_svg: ^2.0.9
   url_launcher: ^6.2.5
   shared_preferences: ^2.2.2
-  flutter_markdown: ^0.6.19
+  flutter_markdown: ^0.6.20+1
   package_info_plus: 5.0.1
   vector_graphics: ^1.1.11+1
   prompt_dialog: ^1.0.15