Update with Zenodo metadata

Author: michamos

citation.cff renamed to CITATION.cff

@@ -8,6 +8,7 @@ authors:
     orcid: https://orcid.org/0000-0002-7638-5686
     affiliation: CERN
 cff-version: 1.2.0
+doi: 10.5281/zenodo.5788551
 license: CC-BY-4.0
 message: "If you use this software, please cite it using these metadata."
 repository-code: "https://github.com/inspirehep/rest-api-doc"

README.md

@@ -1,5 +1,8 @@
 # INSPIRE REST API
 
+[![DOI](https://zenodo.org/badge/269110099.svg)](https://zenodo.org/badge/latestdoi/269110099)
+
+
 [INSPIRE](https://inspirehep.net) is a trusted community hub that helps researchers to share and find accurate scholarly information in high energy physics.
 In addition to a regular web interface for interactive access to its content, a REST API is provided for programmatic access.
 The present document explains how to use this REST API.