Bump System.Security.Cryptography.Xml from 6.0.0 to 9.0.8

---
updated-dependencies:
- dependency-name: System.Security.Cryptography.Xml
  dependency-version: 9.0.8
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

samples/snippets/csharp/VS_Snippets_CLR/HowToSignXMLDocumentRSA/cs/signxml.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="6.0.0" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="9.0.8" />
   </ItemGroup>
 
 </Project>