Bump HtmlAgilityPack from 1.11.27 to 1.11.28

Bumps [HtmlAgilityPack](https://github.com/zzzprojects/html-agility-pack) from 1.11.27 to 1.11.28.
- [Release notes](https://github.com/zzzprojects/html-agility-pack/releases)
- [Commits](zzzprojects/html-agility-pack@v1.11.27...v1.11.28)

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

Rnwood.Smtp4dev/Rnwood.Smtp4dev.csproj

@@ -20,7 +20,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="CommandLiners.MonoOptions" Version="1.0.36" />
-		<PackageReference Include="HtmlAgilityPack" Version="1.11.27" />
+		<PackageReference Include="HtmlAgilityPack" Version="1.11.28" />
 		<PackageReference Include="MailKit" Version="2.9.0" />
 		<PackageReference Include="Microsoft.AspNetCore.Hosting.WindowsServices" Version="3.1.9" />
 		<PackageReference Include="Microsoft.AspNetCore.SignalR" Version="1.1.0" />