Spanish language to be available soon in Forem

Hi everyone!

I am planning to start using Forem in a side project, I would love to have it available in Spanish, additionally to English. I follow Forem since some time, I know French was added long time ago.

I took the freedom to create a Pull Request to add Spanish translations to the main code. Please, find the PR here: https://github.com/forem/forem/pull/20368

What should I do to push this forward? I know the branch is outdated right now. What else should I do to get this PR merged?

PS. I looked for contributing guidelines but I did not find much information.

PS2. I am from Spain. The Spanish language that I added is Castilian Spanish.