(ci deps): Bump xunit.assert from 2.6.5 to 2.6.6 in /build

Bumps [xunit.assert](https://github.com/xunit/xunit) from 2.6.5 to 2.6.6.
- [Commits](xunit/xunit@2.6.5...2.6.6)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

build/Directory.Packages.props

@@ -13,6 +13,6 @@
     <PackageVersion Include="Cake.Docker" Version="1.2.3" />
     <PackageVersion Include="Cake.Git" Version="3.0.0" />
     <PackageVersion Include="Cake.Json" Version="7.0.1" />
-    <PackageVersion Include="xunit.assert" Version="2.6.5" />
+    <PackageVersion Include="xunit.assert" Version="2.6.6" />
   </ItemGroup>
 </Project>