Bump the nuget group with 1 update

Bumps MailKit from 4.14.1 to 4.16.0

---
updated-dependencies:
- dependency-name: MailKit
  dependency-version: 4.16.0
  dependency-type: direct:production
  dependency-group: nuget
...

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Author: dependabot[bot]

Directory.Packages.props

@@ -9,6 +9,7 @@
     <PackageVersion Include="jcamp.FluentEmail.Core" Version="4.0.0" />
     <PackageVersion Include="jcamp.FluentEmail.MailKit" Version="4.0.0" />
     <PackageVersion Include="jcamp.FluentEmail.Smtp" Version="4.0.0" />
+    <PackageVersion Include="MailKit" Version="4.16.0" />
     <!-- Bumped to satisfy Microsoft.VisualStudio.Web.CodeGeneration.Design dependency (>= 17.11.4) -->
     <PackageVersion Include="Microsoft.Build" Version="18.4.0" />
     <PackageVersion Include="Microsoft.Build.Tasks.Core" Version="18.4.0" />