Add GitHub actions/setup-dotnet support

source/Nuke.Common.Tests/CI/ConfigurationGenerationTest.Test_testName=detailed-triggers_attribute=GitHubActionsAttribute.verified.txt

@@ -74,6 +74,11 @@ jobs:
             .nuke/temp
             ~/.nuget/packages
           key: ${{ runner.os }}-${{ hashFiles('**/global.json', '**/*.csproj', '**/Directory.Packages.props') }}
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: |
+            8.0
+            9.0
       - name: 'Run: Test'
         run: ./build.cmd Test
         env:
@@ -122,6 +127,11 @@ jobs:
             .nuke/temp
             ~/.nuget/packages
           key: ${{ runner.os }}-${{ hashFiles('**/global.json', '**/*.csproj', '**/Directory.Packages.props') }}
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: |
+            8.0
+            9.0
       - name: 'Run: Test'
         run: ./build.cmd Test
         env:
@@ -170,6 +180,11 @@ jobs:
             .nuke/temp
             ~/.nuget/packages
           key: ${{ runner.os }}-${{ hashFiles('**/global.json', '**/*.csproj', '**/Directory.Packages.props') }}
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: |
+            8.0
+            9.0
       - name: 'Run: Test'
         run: ./build.cmd Test
         env:

source/Nuke.Common.Tests/CI/ConfigurationGenerationTest.cs

@@ -165,7 +165,8 @@ public class TestBuild : NukeBuild
                     JobConcurrencyCancelInProgress = true,
                     JobConcurrencyGroup = "custom-job-group",
                     EnvironmentName = "environment-name",
-                    EnvironmentUrl = "environment-url"
+                    EnvironmentUrl = "environment-url",
+                    SetupDotNetVersions = new [] { "8.0", "9.0" }
                 }
             );
 

source/Nuke.Common/CI/GitHubActions/Configuration/GitHubActionsSetupDotNetStep.cs

@@ -0,0 +1,36 @@
+// Copyright 2025 Maintainers of NUKE.
+// Distributed under the MIT License.
+// https://github.com/nuke-build/nuke/blob/master/LICENSE
+
+using JetBrains.Annotations;
+using Nuke.Common.Utilities;
+
+namespace Nuke.Common.CI.GitHubActions.Configuration;
+
+// https://github.com/actions/setup-dotnet
+[PublicAPI]
+public class GitHubActionsSetupDotNetStep : GitHubActionsStep
+{
+    public string[] Versions { get; set; }
+
+    public override void Write(CustomFileWriter writer)
+    {
+        writer.WriteLine("- uses: actions/setup-dotnet@v4");
+
+        using (writer.Indent())
+        {
+            writer.WriteLine("with:");
+            using (writer.Indent())
+            {
+                writer.WriteLine("dotnet-version: |");
+                using (writer.Indent())
+                {
+                    foreach (var version in Versions)
+                    {
+                        writer.WriteLine(version);
+                    }
+                }
+            }
+        }
+    }
+}

source/Nuke.Common/CI/GitHubActions/GitHubActionsAttribute.cs

@@ -86,6 +86,8 @@ public GitHubActionsAttribute(
     public string JobConcurrencyGroup { get; set; }
     public bool JobConcurrencyCancelInProgress { get; set; }
 
+    public string[] SetupDotNetVersions { get; set; } = new string[0];
+
     public string[] InvokedTargets { get; set; } = new string[0];
 
     public GitHubActionsSubmodules Submodules
@@ -181,6 +183,14 @@ private IEnumerable<GitHubActionsStep> GetSteps(GitHubActionsImage image, IReadO
                          };
         }
 
+        if (SetupDotNetVersions.Any())
+        {
+            yield return new GitHubActionsSetupDotNetStep
+                         {
+                             Versions = SetupDotNetVersions,
+                         };
+        }
+
         yield return new GitHubActionsRunStep
                      {
                          BuildCmdPath = BuildCmdPath,