Use the new officially supported way to roll forward dotnet global tools

Implemented in [dotnet tool run and install roll-forward option][1].

Supported [since the .NET SDK v8.0.300][2].

Documented in [
.NET tool roll-forward][3].

[1]: dotnet/sdk#37231
[2]: dotnet/sdk@dc2a5fe
[3]: https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/sdk#net-tool-roll-forward

.config/dotnet-tools.json

@@ -6,13 +6,15 @@
       "version": "0.0.1-preview.304",
       "commands": [
         "dotnet-validate"
-      ]
+      ],
+      "rollForward": true
     },
     "dotnet-stryker": {
       "version": "4.0.6",
       "commands": [
         "dotnet-stryker"
-      ]
+      ],
+      "rollForward": true
     }
   }
 }

global.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/global",
   "sdk": {
-    "version": "8.0.100",
+    "version": "8.0.300",
     "allowPrerelease": false,
     "rollForward": "latestFeature"
   }

src/Serilog.Formatting.Log4Net.csproj

@@ -65,7 +65,7 @@
   <Target Name="ValidateNuGetPackage" AfterTargets="Pack">
     <!-- For reference: the file `.config/dotnet-tools.json` was created by running `dotnet new tool-manifest && dotnet tool install dotnet-validate` -->
     <Exec Command="dotnet tool restore" />
-    <Exec Command="dotnet validate package local $([MSBuild]::EnsureTrailingSlash($(PackageOutputPath)))$(PackageId).$(PackageVersion).nupkg" EnvironmentVariables="DOTNET_ROLL_FORWARD=LatestMajor" />
+    <Exec Command="dotnet validate package local $([MSBuild]::EnsureTrailingSlash($(PackageOutputPath)))$(PackageId).$(PackageVersion).nupkg" />
   </Target>
 
 </Project>