chore(deps): update dependency sinon to v21 (googleapis#3705)

Co-authored-by: sofisl <[email protected]>
Co-authored-by: miguel <[email protected]>

Author: 3 people

.github/scripts/package.json

@@ -16,6 +16,6 @@
     "devDependencies": {
         "@octokit/rest": "^19.0.0",
         "mocha": "^10.0.0",
-        "sinon": "^18.0.0"
+        "sinon": "^21.0.0"
     }
 }