Bump Markdig.Signed from 1.0.0 to 1.3.2

---
updated-dependencies:
- dependency-name: Markdig.Signed
  dependency-version: 1.3.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Directory.Packages.props

@@ -32,7 +32,7 @@
     <PackageVersion Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
     <PackageVersion Include="Meziantou.Framework.Win32.CredentialManager" Version="3.0.1" />
     <PackageVersion Include="GitHub.Copilot.SDK" Version="1.0.11" />
-    <PackageVersion Include="Markdig.Signed" Version="1.0.0" />
+    <PackageVersion Include="Markdig.Signed" Version="1.3.2" />
     <PackageVersion Include="Markdown.Avalonia.Tight" Version="12.0.0-a3" />
     <PackageVersion Include="Markdown.Avalonia.SyntaxHigh" Version="12.0.0-a3" />
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="10.0.11" />