Bump the nuget group with 1 update

Bumps System.Security.Cryptography.Xml from 4.4.0 to 4.7.1

---
updated-dependencies:
- dependency-name: System.Security.Cryptography.Xml
  dependency-version: 4.7.1
  dependency-type: direct:production
  dependency-group: nuget
...

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

Author: dependabot[bot]

MailAgent/MailAgent.csproj

@@ -92,6 +92,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.7.1" />
     <EmbeddedResource Remove="obj\**" />
   </ItemGroup>