gh-35666: remove obsolete .zenodo.json* files, update CITATION.cff to fix zenodo/DOI
    
Our DOI creation/update via zenodo is broken again.

`CITATION.cff` overrides `.zenodo.json`, cf.

citation-file-format/citation-file-format#374

This will fix #35659
    
URL: #35666
Reported by: Dima Pasechnik
Reviewer(s): Frédéric Chapoton, Matthias Köppe

Author: Release Manager

.zenodo.json.in

@@ -4,8 +4,8 @@ title: SageMath
 abstract: SageMath is a free open-source mathematics software system.
 authors:
 - name: "The SageMath Developers"
-version: 9.5
+version: 10.0
 doi: 10.5281/zenodo.593563
-date-released: 2022-01-18
+date-released: 2023-05-20
 repository-code: "https://github.com/sagemath/sage"
 url: "https://www.sagemath.org/"

CITATION.cff

@@ -0,0 +1,11 @@
+cff-version: 1.2.0
+message: "If you use this software, please cite it as below."
+title: SageMath
+abstract: SageMath is a free open-source mathematics software system.
+authors:
+- name: "The SageMath Developers"
+version: ${SAGE_VERSION}
+doi: 10.5281/zenodo.593563
+date-released: ${SAGE_RELEASE_DATE}
+repository-code: "https://github.com/sagemath/sage"
+url: "https://www.sagemath.org/"

CITATION.cff.in

@@ -86,17 +86,17 @@ echo "$SAGE_VERSION_BANNER" > "$SAGE_ROOT/VERSION.txt"
 # Regenerate auto-generated files tarball
 "$SAGE_ROOT/bootstrap" -s
 
-# Create json file for Zenodo
+# Create CITATION file for Zenodo-GitHub integration
 export SAGE_VERSION
 export SAGE_RELEASE_DATE
-envsubst <"$SAGE_ROOT/.zenodo.json.in" >"$SAGE_ROOT/.zenodo.json"
+envsubst <"$SAGE_ROOT/CITATION.cff.in" >"$SAGE_ROOT/CITATION.cff"
 
 # Commit auto-generated changes
 git commit -m "Updated SageMath version to $SAGE_VERSION" -- \
     "$SAGE_ROOT/VERSION.txt" \
-    "$SAGE_ROOT/.zenodo.json" \
     "$SAGE_SRC/sage/version.py" \
     "$SAGE_SRC/VERSION.txt" \
+    "$SAGE_ROOT/CITATION.cff" \
     "$SAGE_SRC/bin/sage-version.sh" \
     "$SAGE_ROOT/build/pkgs/configure/checksums.ini" \
     "$SAGE_ROOT/build/pkgs/configure/package-version.txt" \