message: style: add explicit typing
diff: @@ -112,7 +112,7 @@ class Extension {
  private async createPullRequest(): Promise<void> {
  let [owner, repo] = await git.getGitHubOwnerAndRepository(this.cwd);
  const repository = await this.githubManager.getRepository();
  - let pullRequest;
  + let pullRequest: PullRequest|undefined;
  if (repository.parent) {
  let branch: string;
  const items = [{
  