feat: add proxy support (#102)

Adds support for the following environment variables:

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

package.json

@@ -15,7 +15,8 @@
     "@actions/core": "^1.10.1",
     "@octokit/auth-app": "^6.0.3",
     "@octokit/request": "^8.1.6",
-    "p-retry": "^6.2.0"
+    "p-retry": "^6.2.0",
+    "undici": "^6.6.0"
   },
   "devDependencies": {
     "@sinonjs/fake-timers": "^11.2.2",
@@ -25,7 +26,6 @@
     "esbuild": "^0.20.0",
     "execa": "^8.0.1",
     "open-cli": "^8.0.0",
-    "undici": "^6.6.0",
     "yaml": "^2.3.4"
   },
   "release": {