Add Spanish translation

[JoseDeFreitas]

Hello!
I found this repository and thought it is interesting. This kind of information is very useful, especially considering that Git is one of our everyday tools.
I'm a native Spanish speaker who has previously contributed to the translation of other open-source projects and I wanted to translate this project into Spanish. I translated it from the English version.
In this pull request I add the link to the Spanish translation, a repository I created: git-tips.
Let me know if any change is needed.
Thank you in advance.

[JoseDeFreitas]

Hello. For personal reasons, I decided to delete the repository I made with the Spanish translation. Nonetheless, I saved the page in web.archive.org, if you want to keep it and add in somewhere else (link here). Thank you and sorry for the inconvenient.