Pitkant patch citation

[pitkant]

Changes made in a nutshell:

• Added DOI from CRAN (possible conflict with DOI from Zenodo?)
• Updated CITATION so that it updates dates and version numbers automatically, also has a bibentry-key now as well
• Removed old textVersion to rely on the automatically formed APA-style citation

I noticed, while intending to cite geofi in a publication, that the citation, or more specifically the citation("geofi") for geofi CRAN release 1.0.18 was inadvertently out of date. I changed the CITATION file so that it now automatically updates the year and version number of the package in the citation. I also removed the textVersion field since it is easily forgotten and becomes out-of-date as well. Without the textVersion field the citation() function outputs a normal text citation

Kainu M, Lehtomaki J, Parkkinen J, Miettinen J, Kantanen P, Vesanen S, Lahti L (2025). 
_geofi: Access Finnish Geospatial Data_. doi:10.32614/CRAN.package.geofi 
<https://doi.org/10.32614/CRAN.package.geofi>, 
R package version 1.0.18,<https://github.com/rOpenGov/geofi>.

as I would anyway prefer it to.

Of course this is a matter of opinion so feel free to reject my PR if the old style

(C) Markus Kainu, Joona Lehtomaki, Juuso Parkkinen, Jani Miettinen, Pyry Kantanen, Sampo Vesanen, Leo Lahti 2015-2025.
  geofi: Access Finnish Geospatial Data, <doi:10.5281/zenodo.7148138>

was more preferable.

[muuankarski]

Thanks @pitkant- greatly appreciated!