The project include a CITATION.cff file to indicate how to cite the software

### Description
Once you get a unique identifier for your software (see guideline #49 ), you should indicate to user how to properly cite your work. This is formally done with a *CITATION.cff* file, which is a machine readable file that typically seats at the root level of the repository. Github will recognize automatically it and use it to populate a "Cite this repository" tab on the right side menu (see example below).

All details about this file format can be found in here: https://citation-file-format.github.io
And a very good online CITATION.cff creator is also provided at: https://citation-file-format.github.io/cff-initializer-javascript

**In order to ease citation of your work and to make your software findable (FAIR4RS), we strongly recommend to also provide unique identifiers in the README file**. See guidelines #28

### Example

```cff
cff-version: 1.2.0
title: argopy
message: 'If you use this software, please cite it as below.'
type: software
authors:
- family-names: Maze
given-names: Guillaume
orcid: 'https://orcid.org/0000-0001-7231-2095'
- family-names: Balem
given-names: Kevin
orcid: 'https://orcid.org/0000-0002-4956-8698'
identifiers:
- type: doi
value: 10.21105/joss.02425
description: DOI of the JOSS peer-reviewed article, preferred citation
- type: swh
value: 'swh:1:dir:3d568702945207a22ac35e038256e4be88d20f17'
description: Software Heritage Identifier (SWHID)
- type: doi
value: 10.5281/zenodo.4010160
description: Zenodo archives of the repository
repository-code: 'https://github.com/euroargodev/argopy'
url: 'https://github.com/euroargodev/argopy'
repository: 'https://argopy.readthedocs.io'
abstract: A python library for Argo data beginners and experts
license: EUPL-1.2
preferred-citation:
type: article
authors:
- family-names: Maze
given-names: Guillaume
orcid: 'https://orcid.org/0000-0001-7231-2095'
- family-names: Balem
given-names: Kevin
orcid: 'https://orcid.org/0000-0002-4956-8698'
doi: 10.21105/joss.02425
journal: Journal of Open Source Software
title: 'argopy: A Python library for Argo ocean data analysis'
year: 2020
volume: 5
issue: 53
page: 2425
```

### Misc
As a consequence, Github detect this file to populate the right hand-side menu: