Update dependency ICSharpCode.Decompiler to v9

Author: dependencyupdates[bot]

src/Directory.Packages.props

@@ -11,7 +11,7 @@
     <PackageVersion Include="Azure.Messaging.ServiceBus" Version="7.20.1" />
     <PackageVersion Include="Azure.Monitor.Query.Metrics" Version="1.0.0" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
-    <PackageVersion Include="ICSharpCode.Decompiler" Version="8.2.0.7535" />
+    <PackageVersion Include="ICSharpCode.Decompiler" Version="9.1.0.7988" />
     <PackageVersion Include="Microsoft.Data.SqlClient" Version="5.2.3" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageVersion Include="Mindscape.Raygun4Net.AspNetCore" Version="11.2.3" />