FIX: bumpversion rule for CITATION.cff

Author: Thibault Cordier

.bumpversion.cfg

@@ -16,6 +16,6 @@ search = version = "{current_version}"
 replace = version = "{new_version}"
 
 [bumpversion:file:CITATION.cff]
-search = version = "{current_version}"
-replace = version = "{new_version}"
+search = version: {current_version}
+replace = version: {new_version}