Add "hacktoberfest" repository topic

[witoszekdev]

Please add the "hacktoberfest" repository topic to allow completion of the Hacktoberfest challenge 🙏
It's already present on the 30-seconds-of-code repository 😉

[Chalarangelo]

Sorry, but we've made a conscious decision here to not accept snippets in all repositories due to the high amounts of new users trying to contribute and the large amount of spam PRs we are getting. For this year's Hacktoberfest we are only accepting content in the JS and Python repos, so no hacktoberfest topic or hacktoberfest-accepted label on any other repos. Cheers.