Replacing a label with another appears to work in vscode but doesn't (#4496)

Part of #4492

Author: alexr00

src/github/createPRViewProvider.ts

@@ -413,7 +413,7 @@ export class CreatePullRequestViewProvider extends WebviewViewBase implements vs
 
 	private async setLabels(pr: PullRequestModel, labels: ILabel[]): Promise<void> {
 		if (labels.length > 0) {
-			await pr.addLabels(labels.map(label => label.name));
+			await pr.setLabels(labels.map(label => label.name));
 		}
 	}
 

src/github/issueModel.ts

@@ -249,10 +249,10 @@ export class IssueModel<TItem extends Issue = Issue> {
 		}
 	}
 
-	async addLabels(labels: string[]): Promise<void> {
+	async setLabels(labels: string[]): Promise<void> {
 		const { octokit, remote } = await this.githubRepository.ensure();
 		try {
-			await octokit.call(octokit.api.issues.addLabels, {
+			await octokit.call(octokit.api.issues.setLabels, {
 				owner: remote.owner,
 				repo: remote.repositoryName,
 				issue_number: this.number,

src/github/issueOverview.ts

@@ -241,7 +241,7 @@ export class IssueOverviewPanel<TItem extends IssueModel = IssueModel> extends W
 			);
 
 			if (labelsToAdd && labelsToAdd.length) {
-				await this._item.addLabels(labelsToAdd.map(r => r.label));
+				await this._item.setLabels(labelsToAdd.map(r => r.label));
 				const addedLabels: ILabel[] = labelsToAdd.map(label => newLabels.find(l => l.name === label.label)!);
 
 				this._item.item.labels = addedLabels;