message: github_updater: handle null descriptions and last pushed dates
diff: @@ -259,7 +259,7 @@ impl GithubUpdater {
  &repo.id,
  &repo.name_with_owner,
  &repo.description,
  - &repo.pushed_at.naive_utc(),
  + &repo.pushed_at.map(|time| time.naive_utc()),
  &(repo.stargazer_count as i32),
  &(repo.fork_count as i32),
  &(repo.issues.total_count as i32),
  @@ -350,8 +350,8 @@ struct GraphRepositoryNode {
  struct GraphRepository {
  id: String,
  name_with_owner: String,
  - pushed_at: DateTime<Utc>,
  - description: String,
  + pushed_at: Option<DateTime<Utc>>,
  + description: Option<String>,
  stargazer_count: i64,
  fork_count: i64,
  issues: GraphIssues,
  