CITATION.cff: Remove YAML formatting

GitHub says it can't parse my CITATION.cff file. The example in the
docs shows version 1.2.0 also, I wonder if that's relevant.

See: https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/creating-a-repository-on-github/about-citation-files

CITATION.cff

@@ -0,0 +1,19 @@
+cff-version: "1.1.0"
+abstract: "A simple but opinionated metadata quality checker and fixer designed to work with CSVs in the DSpace ecosystem."
+authors: 
+  -
+    affiliation: "International Livestock Research Institute"
+    family-names: Orth
+    given-names: "Alan S."
+    orcid: "https://orcid.org/0000-0002-1735-7458"
+date-released: 2019-07-26
+doi: "10568/110997"
+keywords: 
+  - dspace
+  - "dublin-core"
+  - csv
+  - metadata
+license: "GPL-3.0-only"
+message: "If you use this software, please cite it using these metadata."
+repository-code: "https://github.com/ilri/csv-metadata-quality"
+title: "DSpace CSV Metadata Quality Checker"