Update dependency mithril to v2.3.4

Author: renovate[bot]

libraries/mithril/package.json

@@ -18,7 +18,7 @@
     "webpack": "5.101.0"
   },
   "dependencies": {
-    "mithril": "2.2.2"
+    "mithril": "2.3.4"
   },
   "wireit": {
     "test": {