Revert "Fix build"

This reverts commit 21bf926.

Author: Rico Suter

build/Build.CI.GitHubActions.cs

@@ -49,7 +49,6 @@ protected override GitHubActionsJob GetJobs(GitHubActionsImage image, IReadOnlyC
 
         // only need to list the ones that are missing from default image
         newSteps.Insert(0, new GitHubActionsSetupDotNetStep(new[] { "2.1.*" }));
-        newSteps.Insert(0, new GitHubActionsSetupDotNetStep(new[] { "5.0.*" }));
 
         newSteps.Insert(0, new GitHubActionsUseGnuTarStep());
         newSteps.Insert(0, new GitHubActionsConfigureLongPathsStep());