fix(api): add duplex configuration to fetch (#19)

Node sneakily introduced a change to the fetch API that now requires that the `duplex` option be set on all requests with contain a payload body: nodejs/node#46221 , which means that the CLI now fails on node >18.13, >19.1, 20, and running the CLI on those versions will cause the following exception:
```
RequestInit: duplex option is required when sending a body.

Exited with code exit status 1
```

This configures all fetch requests with bodies to set the duplex option to the only value that is allowed by the spec for now, which is `"half"`. This should have no impact on older node versions since it's the only option available, but will allow the CLI to run on those newer versions without throwing an error.

src/apiClient.js

@@ -52,6 +52,7 @@ class ApiClient {
       method: 'POST',
       headers: this.headers,
       body: JSON.stringify(data),
+      duplex: 'half',
     });
   }
 
@@ -110,6 +111,7 @@ class ApiClient {
       maxRetryDelay,
       method: 'PUT',
       body: contents,
+      duplex: 'half',
     });
 
     if (this._gcsBucket) {
@@ -123,6 +125,7 @@ class ApiClient {
           name: fileData.name,
           bucket: this._gcsBucket,
         }),
+        duplex: 'half',
       });
     }