Use commander preAction hook for setMode

Hooks are new to commander v8. We can use hooks to ensure that `setMode`
is called before every command is invoked.

node_modules/commander/package-support.json

@@ -0,0 +1,16 @@
+{
+  "versions": [
+    {
+      "version": "*",
+      "target": {
+        "node": "supported"
+      },
+      "response": {
+        "type": "time-permitting"
+      },
+      "backing": {
+        "npm-funding": true
+      }
+    }
+  ]
+}