Bump Verify.NUnit from 31.4.3 to 31.5.1

---
updated-dependencies:
- dependency-name: Verify.NUnit
  dependency-version: 31.5.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/Directory.Packages.props

@@ -12,7 +12,7 @@
     <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.12" />
     <PackageVersion Include="Verify" Version="31.4.3" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.2" />
-    <PackageVersion Include="Verify.Nunit" Version="31.4.3" />
+    <PackageVersion Include="Verify.Nunit" Version="31.5.1" />
     <PackageVersion Include="Microsoft.Sbom.Targets" Version="4.1.3" />
   </ItemGroup>
 </Project>