Update dependency sinon to v20 (#1356)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -95,7 +95,7 @@
     "qunit": "2.24.1",
     "release-plan": "^0.13.1",
     "rsvp": "4.8.5",
-    "sinon": "19.0.5",
+    "sinon": "20.0.0",
     "stylelint": "16.16.0",
     "stylelint-config-standard": "37.0.0",
     "stylelint-prettier": "5.0.3",