Bump the dotnet group with 2 updates (#68)

Bumps Markdig from 1.4.0 to 1.4.1
Bumps Verify.TUnit from 33.3.3 to 33.3.4

---
updated-dependencies:
- dependency-name: Markdig
  dependency-version: 1.4.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
- dependency-name: Verify.TUnit
  dependency-version: 33.3.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

MarkupString.Tests/MarkupString.Tests.csproj

@@ -12,11 +12,11 @@
     <PackageReference Include="TUnit" Version="1.75.0" />
     <!-- A GitHub-flavoured Markdown reader, so the Markdown tests check what a reader makes of the output
          rather than only the characters written. -->
-    <PackageReference Include="Markdig" Version="1.4.0" />
+    <PackageReference Include="Markdig" Version="1.4.1" />
     <!-- Verify.TUnit carries a floor on TUnit.Core. Bump the two together: if NuGet lifts
          TUnit.Core past the TUnit.Engine this project asks for, the split versions fault at
          startup with MissingFieldException rather than failing to restore. -->
-    <PackageReference Include="Verify.TUnit" Version="33.3.3" />
+    <PackageReference Include="Verify.TUnit" Version="33.3.4" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\MarkupString\MarkupString.csproj" />