[GRASS-git] [OSGeo/grass] 290821: docs: fix syntax of CITATION.cff file (#3123)

[Markus Neteler]

  Branch: refs/heads/releasebranch_8_2
  Home:   https://github.com/OSGeo/grass
  Commit: 29082111b80cae36d20c3d12f8e4e8d62218dfc7
      https://github.com/OSGeo/grass/commit/29082111b80cae36d20c3d12f8e4e8d62218dfc7
  Author: Markus Neteler <neteler at osgeo.org>
  Date:   2023-08-15 (Tue, 15 Aug 2023)

  Changed paths:
    M CITATION.cff

  Log Message:
  -----------
  docs: fix syntax of CITATION.cff file (#3123)

Syntax errors fixed (needed for Zenodo.org auto-upload and also in general).

Validated successfully:

```
cffconvert --validate
Citation metadata are valid according to schema version 1.2.0.
```

with

```
cffconvert --version
3.0.0a0
```