When using the octokit client from the `@actions/github` library to make requests through an authenticated proxy, the user/password creds are not properly encoded in the `Proxy-Authorization` header. If I have an env var like the following: ``` https_proxy=http://username:password@hostname:port/ ``` And sniff the outgoing network request, I can see that the `Proxy-Authorization` header is set to the following: ``` Proxy-Authorization: username:password ``` The [correct value](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Proxy-Authorization) should be a base64-encoded basic auth value: ``` Proxy-Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ= ``` The issue is with the following line: https://github.com/actions/toolkit/blob/faf9cb2ea2116bae86cba614d9b1ac7faf04ce69/packages/http-client/src/index.ts#L729 The `token` value being passed to the `ProxyAgent` is the un-encoded username/password pair. However, according to the documentation for the `undici` library (https://undici.nodejs.org/#/docs/api/ProxyAgent?id=example-basic-proxy-request-with-authentication), the supplied token needs to be pre-encoded: ``` token: `Basic ${Buffer.from('username:password').toString('base64')}` ```