feat: add GitHub Enterprise Server (GHES) support (actions#36)

This adds support for this action to be used in GitHub Enterprise
Server.

It sends request to the base url extracted from
[GITHUB_API_URL](https://docs.github.com/en/enterprise-server@3.10/actions/learn-github-actions/variables#default-environment-variables).

---------

Co-authored-by: Gregor Martynus <39992+gr2m@users.noreply.github.com>

lib/post.js

@@ -11,7 +11,7 @@ export async function post(core, request) {
   const token = core.getState("token");
 
   if (!token) return;
-  
+
   await request("DELETE /installation/token", {
     headers: {
       authorization: `token ${token}`,

main.js

@@ -15,9 +15,16 @@ const privateKey = core.getInput("private_key");
 
 const repository = process.env.GITHUB_REPOSITORY;
 
-main(appId, privateKey, repository, core, createAppAuth, request).catch(
-  (error) => {
-    console.error(error);
-    core.setFailed(error.message);
-  }
-);
+main(
+  appId,
+  privateKey,
+  repository,
+  core,
+  createAppAuth,
+  request.defaults({
+    baseUrl: process.env["GITHUB_API_URL"],
+  })
+).catch((error) => {
+  console.error(error);
+  core.setFailed(error.message);
+});

post.js

@@ -5,9 +5,12 @@ import { request } from "@octokit/request";
 
 import { post } from "./lib/post.js";
 
-post(core, request).catch(
-  (error) => {
-    console.error(error);
-    core.setFailed(error.message);
-  }
-);
+post(
+  core,
+  request.defaults({
+    baseUrl: process.env["GITHUB_API_URL"],
+  })
+).catch((error) => {
+  console.error(error);
+  core.setFailed(error.message);
+});