fix: resolve the bug where gists sometimes do not load properly (#7)

This fix resolves the issue where the `igist` list sometimes returns empty after a lengthy processing time by using `igist--request` instead of `ghub-request`.

Additionally, this fix addresses another bug introduced by the latest version of ghub (magit/ghub@2061136), where only the first page of gists was loaded, and subsequent pages were not fetched.

Issue: #7