add the template for zenodo json, and the way to fill in it

Author: dimpase

.zenodo.json.in

@@ -0,0 +1,27 @@
+{
+    "description": "Mirror of the Sage https://sagemath.org/ source tree", 
+    "license": "other-open", 
+    "title": "sagemath/sage: ${SAGE_VERSION}", 
+    "version": "${SAGE_VERSION}", 
+    "upload_type": "software", 
+    "publication_date": "${SAGE_RELEASE_DATE}", 
+    "creators": [
+        {
+            "affiliation": "SageMath.org", 
+            "name": "The SageMath Developers"
+        }
+    ], 
+    "access_right": "open", 
+    "related_identifiers": [
+        {
+            "scheme": "url", 
+            "identifier": "https://github.com/sagemath/sage/tree/${SAGE_VERSION}", 
+            "relation": "isSupplementTo"
+        }, 
+        {
+            "scheme": "doi", 
+            "identifier": "10.5281/zenodo.593563", 
+            "relation": "isVersionOf"
+        }
+    ]
+}

src/bin/sage-update-version

@@ -62,6 +62,11 @@ echo "$SAGE_VERSION_BANNER" > "$SAGE_ROOT/VERSION.txt"
 # Regenerate auto-generated files tarball
 "$SAGE_ROOT/bootstrap" -s
 
+# Create json file for Zenodo
+export SAGE_VERSION
+export SAGE_RELEASE_DATE
+envsubst <"$SAGE_ROOT/.zenodo.json.in" >"$SAGE_ROOT/.zenodo.json"
+
 # Commit auto-generated changes
 git commit -m "Updated SageMath version to $SAGE_VERSION" -- \
     "$SAGE_ROOT/VERSION.txt" \