docs(readme): fix https proxy example (#352)

README.md

@@ -301,7 +301,7 @@ If you would like to disable or customize this behavior, for example to use the
 <!-- prettier-ignore -->
 ```ts
 import http from 'http';
-import HttpsProxyAgent from 'https-proxy-agent';
+import { HttpsProxyAgent } from 'https-proxy-agent';
 
 // Configure the default for all requests:
 const modernTreasury = new ModernTreasury({
@@ -310,9 +310,8 @@ const modernTreasury = new ModernTreasury({
 
 // Override per-request:
 await modernTreasury.externalAccounts.list({
-  baseURL: 'http://localhost:8080/test-api',
   httpAgent: new http.Agent({ keepAlive: false }),
-})
+});
 ```
 
 ## Semantic Versioning