Bump TUnit from 1.18.9 to 1.18.21

---
updated-dependencies:
- dependency-name: TUnit
  dependency-version: 1.18.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Directory.Packages.props

@@ -9,6 +9,6 @@
     <PackageVersion Include="Microsoft.Extensions.Hosting" Version="10.0.3" />
     <PackageVersion Include="MinVer" Version="7.0.0" />
     <PackageVersion Include="Testcontainers.MsSql" Version="4.10.0" />
-    <PackageVersion Include="TUnit" Version="1.18.9" />
+    <PackageVersion Include="TUnit" Version="1.18.21" />
   </ItemGroup>
 </Project>