Correctly migrate duplicate clusters in workspaces (#3211)

- Keep track of the set of all workspaces that each duplicated entry was
  a part of

Signed-off-by: Sebastian Malton <sebastian@malton.name>

src/main/cluster.ts

@@ -120,6 +120,10 @@ export class Cluster implements ClusterModel, ClusterState {
    * @deprecated
    */
   @observable workspace: string;
+  /**
+   * @deprecated
+   */
+  @observable workspaces: string[];
   /**
    * Kubernetes API server URL
    *
@@ -294,6 +298,10 @@ export class Cluster implements ClusterModel, ClusterState {
       this.workspace = model.workspace;
     }
 
+    if (model.workspaces) {
+      this.workspaces = model.workspaces;
+    }
+
     if (model.contextName) {
       this.contextName = model.contextName;
     }
@@ -589,6 +597,7 @@ export class Cluster implements ClusterModel, ClusterState {
       contextName: this.contextName,
       kubeConfigPath: this.kubeConfigPath,
       workspace: this.workspace,
+      workspaces: this.workspaces,
       preferences: this.preferences,
       metadata: this.metadata,
       accessibleNamespaces: this.accessibleNamespaces,