Update GEM solar and wind datasets to May-2023.

[Tomkourou]

Closes # (if applicable).

Change proposed in this Pull Request

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other

Checklist

• I have added a note to release notes doc/release_notes.rst.
• I have used pre-commit run --all to lint/format/check my contribution
• I have documented the effects of my code changes in the documentation doc/.
• I have adjusted the docstrings in the code appropriately.

[davide-f]

Hello!
Nice update! I think comment by @FabianHofmann may be welcome.
Personally, I think we should avoid the manual update from Jan to May, etc.
I understand that the pointed resource is stored in @pz-max github. I think it would be best to always name in github a file "..._latest" so that there is no need to open a PR every month.

What do you think? @FabianHofmann @Tomkourou @pz-max

[pz-max]

Agree with @davide-f. Great suggestion! This allows us to be more flexible.
I am creating a copy and call it latest in my data repo.

Update: DONE https://github.com/pz-max/gem-powerplant-data

TODO: now we only need to change the links in powerplantmatching

Ideally, we talk with GEM that they also have something like latest & we get the link from them

[Tomkourou]

Agree that's probably wise :)

[FabianHofmann]

Very good idea!

[FabianHofmann]

Let's merge this for now and set up the "latest" reference later