Add pre-commit hook to validate CITATION.cff

Author: alexdewar

.pre-commit-config.yaml

@@ -69,3 +69,7 @@ repos:
       - id: codespell
         args: [--ignore-words, .codespell_ignore.txt]
         exclude: \.svg$
+  - repo: https://github.com/citation-file-format/cffconvert
+    rev: b6045d78aac9e02b039703b030588d54d53262ac
+    hooks:
+      - id: validate-cff