Use node built-in fetch (#3246)

Node `fetch` built-in function is now out of experimental since node
`18.13.0` this allows us to not have some partial implementation and get
rid of an external dependency

Author: timotheeguerin

.chronus/changes/use-node-fetch-builtin-2024-3-26-17-50-57.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/compiler"
+---
+
+Internals: Use node built-in `fetch` API that is now stable since node `18.13.0`

packages/compiler/package.json

@@ -85,7 +85,6 @@
     "@babel/code-frame": "~7.24.2",
     "ajv": "~8.12.0",
     "change-case": "~5.4.4",
-    "follow-redirects": "^1.15.6",
     "globby": "~14.0.1",
     "mustache": "~4.2.0",
     "picocolors": "~1.0.0",
@@ -99,7 +98,6 @@
   },
   "devDependencies": {
     "@types/babel__code-frame": "~7.0.6",
-    "@types/follow-redirects": "^1.14.4",
     "@types/mustache": "~4.2.5",
     "@types/node": "~18.11.19",
     "@types/prompts": "~2.4.9",

packages/compiler/src/core/fetch.ts

@@ -2,7 +2,6 @@ import { realpath } from "fs";
 import { mkdir, readdir, readFile, rm, stat, writeFile } from "fs/promises";
 import { fileURLToPath, pathToFileURL } from "url";
 import { findProjectRoot } from "../utils/misc.js";
-import { fetch } from "./fetch.js";
 import { createConsoleSink } from "./logger/index.js";
 import { joinPaths } from "./path-utils.js";
 import { createSourceFile, getSourceFileKindFromExt } from "./source-file.js";
@@ -16,7 +15,7 @@ export const CompilerPackageRoot = (await findProjectRoot(stat, fileURLToPath(im
  */
 export const NodeHost: CompilerHost = {
   readUrl: async (url: string) => {
-    const response = await fetch(url);
+    const response = await fetch(url, { redirect: "follow" });
     const text = await response.text();
     return createSourceFile(text, response.url);
   },