docs: fix defaultMachine to machine in config-file

Author: isshaddad

docs/config/config-file.mdx

@@ -297,7 +297,7 @@ import { defineConfig } from "@trigger.dev/sdk";
 export default defineConfig({
   project: "<project ref>",
   // Your other config settings...
-  defaultMachine: "large-1x",
+  machine: "large-1x",
 });
 ```