GeoSpark repo has been moved to Apache

[Jia Yu <ji...@apache.org>]

Hi Sedona users and committers,

The Sedona repo is now here: https://github.com/apache/incubator-sedona

I am now working on refactoring the code and website. This may take a few
weeks.

Committers:

1. Link your GitHub ID to your Apache account. You will be added to
"Apache" on GitHub in a few minutes. https://selfserve.apache.org/  Choose
"Edit your ASF Identity"

2. Visit this website to merge your Apache ID with your GitHub account:
https://gitbox.apache.org/setup/ You will be added to the incubator
committers and sedona committers on GitHub in a few minutes.

3. Click any file in the GitHub repo and see whether you have the write
access to it. You don't have to actually commit anything. The UI will show
you the permission.

Thanks,
Jia