fix(deps): update dependency luxon to v1.21.1

Author: renovate-bot

package-lock.json

@@ -6,7 +6,7 @@
     "js-worker-search": "1.4.0",
     "localforage": "1.7.3",
     "lodash.debounce": "4.0.8",
-    "luxon": "1.12.1",
+    "luxon": "1.21.1",
     "prop-types": "15.7.2",
     "react": "16.8.6",
     "react-dom": "16.8.6",