Update cake monorepo to v6

Author: renovate[bot]

demo/dsl/.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "cake.tool": {
-      "version": "4.0.0",
+      "version": "6.0.0",
       "commands": [
         "dotnet-cake"
       ]

demo/frosting/build/Build.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="JetBrains.Annotations" Version="2025.2.4" />
-    <PackageReference Include="Cake.Frosting" Version="4.0.0" />
+    <PackageReference Include="Cake.Frosting" Version="6.0.0" />
     <ProjectReference Include="$(ProjectDir)../../../src/Cake.AzurePipelines.Module/Cake.AzurePipelines.Module.csproj" />
     <ProjectReference Include="$(ProjectDir)../../../src/Cake.GitHubActions.Module/Cake.GitHubActions.Module.csproj" />
     <ProjectReference Include="$(ProjectDir)../../../src/Cake.MyGet.Module/Cake.MyGet.Module.csproj" />