Remove auth method only used in runner

src/util.ts

@@ -1,7 +1,6 @@
 import * as fs from "fs";
 import * as os from "os";
 import * as path from "path";
-import { Readable } from "stream";
 import { promisify } from "util";
 
 import * as core from "@actions/core";
@@ -397,71 +396,6 @@ export function apiVersionInRange(
   return undefined;
 }
 
-/**
- * Retrieves the github auth token for use with the runner. There are
- * three possible locations for the token:
- *
- * 1. from the cli (considered insecure)
- * 2. from stdin
- * 3. from the GITHUB_TOKEN environment variable
- *
- * If both 1 & 2 are specified, then an error is thrown.
- * If 1 & 3 or 2 & 3 are specified, then the environment variable is ignored.
- *
- * @param githubAuth a github app token or PAT
- * @param fromStdIn read the github app token or PAT from stdin up to, but excluding the first whitespace
- * @param readable the readable stream to use for getting the token (defaults to stdin)
- *
- * @return a promise resolving to the auth token.
- */
-export async function getGitHubAuth(
-  logger: Logger,
-  githubAuth: string | undefined,
-  fromStdIn: boolean | undefined,
-  readable = process.stdin as Readable
-): Promise<string> {
-  if (githubAuth && fromStdIn) {
-    throw new Error(
-      "Cannot specify both `--github-auth` and `--github-auth-stdin`. Please use `--github-auth-stdin`, which is more secure."
-    );
-  }
-
-  if (githubAuth) {
-    logger.warning(
-      "Using `--github-auth` via the CLI is insecure. Use `--github-auth-stdin` instead."
-    );
-    return githubAuth;
-  }
-
-  if (fromStdIn) {
-    return new Promise((resolve, reject) => {
-      let token = "";
-      readable.on("data", (data) => {
-        token += data.toString("utf8");
-      });
-      readable.on("end", () => {
-        token = token.split(/\s+/)[0].trim();
-        if (token) {
-          resolve(token);
-        } else {
-          reject(new Error("Standard input is empty"));
-        }
-      });
-      readable.on("error", (err) => {
-        reject(err);
-      });
-    });
-  }
-
-  if (process.env.GITHUB_TOKEN) {
-    return process.env.GITHUB_TOKEN;
-  }
-
-  throw new Error(
-    "No GitHub authentication token was specified. Please provide a token via the GITHUB_TOKEN environment variable, or by adding the `--github-auth-stdin` flag and passing the token via standard input."
-  );
-}
-
 /**
  * This error is used to indicate a runtime failure of an exhaustivity check enforced at compile time.
  */