Bump System.IO.Packaging from 7.0.0 to 8.0.0

Bumps [System.IO.Packaging](https://github.com/dotnet/runtime) from 7.0.0 to 8.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v7.0.0...v8.0.0)

---
updated-dependencies:
- dependency-name: System.IO.Packaging
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

ApiDoctor.Validation/ApiDoctor.Validation.csproj

@@ -27,6 +27,6 @@
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="System.CodeDom" Version="8.0.0" />
     <PackageReference Include="System.Data.DataSetExtensions" Version="4.5.0" />
-    <PackageReference Include="System.IO.Packaging" Version="7.0.0" />
+    <PackageReference Include="System.IO.Packaging" Version="8.0.0" />
   </ItemGroup>
 </Project>