Update to node20

- updates many dependencies
- removes @nuxtjs/tailwindcss and postcss8
- pkg targets are using node18 until node20 targets are available

.devcontainer/devcontainer.json

@@ -8,7 +8,7 @@
 		// Append -bullseye or -buster to pin to an OS version.
 		// Use -bullseye variants on local arm64/Apple Silicon.
 		"args": {
-			"VARIANT": "16"
+			"VARIANT": "20"
 		}
 	},
 	"mounts": [