Add Topics to EditChange struct

[riaje]

Hi,

I want to add the missing Topics field for the EditChange struct.

In my case, it will allow me to retrieve the previous topics when I receive the repository edited event.

I already have the branch ready for review.

Thanks

[gmlewis]

Sounds great, thanks, @riaje !
Our CONTRIBUTING.md guide has helpful information in it for submitting PRs if you are new to this repo.
Specifically, step 4 seems to be a commonly-missed step.

[riaje]

Already read 👍 thanks for the reminder of course !
The PR is submit, it's my first contribution to an open project on GitHub so I discover the process in the same time 😆
Thanks