feat: add proxy support (#102)

Adds support for the following environment variables:

- `https_proxy`
- `HTTPS_PROXY`
- `http_proxy`
- `HTTP_PROXY`
- `no_proxy`
- `NO_PROXY`

post.js

@@ -5,9 +5,7 @@ import core from "@actions/core";
 import { post } from "./lib/post.js";
 import request from "./lib/request.js";
 
-const baseUrl = core.getInput("github-api-url").replace(/\/$/, "");
-
-post(core, request.defaults({ baseUrl })).catch((error) => {
+post(core, request).catch((error) => {
   /* c8 ignore next 3 */
   console.error(error);
   core.setFailed(error.message);