some work for loading a workspace

ModpackUpdater.Apps.Manager/Features/Workspaces/GitLabRepo/GitLabRepoWorkspaceFeature.cs

@@ -17,7 +17,7 @@ internal class GitLabRepoWorkspaceFeature : WorkspaceFeature, IPluginFeatureProv
         Icon = AppGlobals.Symbols.GetSvgImage(AppSymbols.gitlab, SymbolSize.Small);
     }
 
-    protected override bool OnConfigure(ref IWorkspace workspace)
+    protected override bool OnConfigure(ref IWorkspace? workspace)
     {
         var settings = workspace?.Config as GitLabRepoWorkspaceConfig ?? new();
 
@@ -25,6 +25,15 @@ internal class GitLabRepoWorkspaceFeature : WorkspaceFeature, IPluginFeatureProv
             return false;
 
         workspace = new GitLabRepoWorkspace(settings);
+
         return true;
     }
+
+    protected override void OnCreate(out IWorkspace workspace, WorkspaceConfig config)
+    {
+        if (config is not GitLabRepoWorkspaceConfig gitlabConfig)
+            throw new NotImplementedException($"Only configs of type {typeof(GitLabRepoWorkspaceConfig).Name} are allowed.");
+
+        workspace = new GitLabRepoWorkspace(gitlabConfig);
+    }
 }