Add hacktoberfest topic to the repo
Hacktoberfest 2020 has undergone some changes due to the excessive spamming that occurred this year. The rules for a PR to be accepted have been modified. Detailed post on their official website can be found [here](https://hacktoberfest.digitalocean.com/hacktoberfest-update).

Here is the most important part for maintainers:

![](https://user-images.githubusercontent.com/44412790/94985906-ef5c9000-0577-11eb-9eaa-850fcd0b0942.png)

As one can see, the maintainers need to add the `hacktoberfest` topic to the repo in order for all the PRs to be considered valid. This is completely opt-in and this issue serves as a notification for the maintainers in case they want to take part.