message: feat(vscode-github): allow to open pull request
  After successful creation of pull request allow to open it on github
  Closes
diff: @@ -106,7 +106,7 @@ class Extension {
  const pullRequest = await this.githubManager.createPullRequest();
  if (pullRequest) {
  this.statusBarManager.updateStatus();
  - vscode.window.showInformationMessage(`Successfully created #${pullRequest.number}`);
  + this.showPullRequestNotification(pullRequest);
  }
  }
  @@ -142,7 +142,15 @@ class Extension {
  }
  if (pullRequest) {
  this.statusBarManager.updateStatus();
  - vscode.window.showInformationMessage(`Successfully created #${pullRequest.number}`);
  + this.showPullRequestNotification(pullRequest);
  + }
  + }
  +
  + private async showPullRequestNotification(pullRequest: PullRequest): Promise<void> {
  + const result = await vscode.window.showInformationMessage(
  + `Successfully created #${pullRequest.number}`, 'Open on Github');
  + if (result) {
  + vscode.commands.executeCommand('vscode.open', vscode.Uri.parse(pullRequest.html_url));
  }
  }
  