fix!: require NODE_USE_ENV_PROXY for proxy support (#342)

BREAKING CHANGE: Custom proxy handling has been removed. If you use HTTP_PROXY or HTTPS_PROXY, you must now also set NODE_USE_ENV_PROXY=1 on the action step.

post.js

@@ -3,9 +3,15 @@
 import * as core from "@actions/core";
 
 import { post } from "./lib/post.js";
-import request from "./lib/request.js";
+import request, { ensureNativeProxySupport } from "./lib/request.js";
 
-post(core, request).catch((error) => {
+async function run() {
+  ensureNativeProxySupport();
+
+  return post(core, request);
+}
+
+run().catch((error) => {
   /* c8 ignore next 3 */
   console.error(error);
   core.setFailed(error.message);