fix: set proper User-Agent header on outgoing HTTP requests

Yarn currently sends 'got (https://github.com/sindresorhus/got)' as the
User-Agent header, making it impossible to distinguish Yarn traffic.

Set it to follow the convention used by npm and pnpm:
yarn/<version> node/<node_version>

Fixes #7146

Author: god032396-del

packages/yarnpkg-core/sources/httpUtils.ts

@@ -12,6 +12,7 @@ import {ReportError}                              from './Report';
 import * as formatUtils                           from './formatUtils';
 import {MapValue, MapValueToObjectValue}          from './miscUtils';
 import * as miscUtils                             from './miscUtils';
+import {YarnVersion}                              from './YarnVersion';
 
 export type {RequestError}                       from 'got';
 
@@ -238,7 +239,8 @@ async function requestImpl(target: string | URL, body: Body, {configuration, hea
   if (url.protocol === `http:` && !micromatch.isMatch(url.hostname, configuration.get(`unsafeHttpWhitelist`)))
     throw new ReportError(MessageName.NETWORK_UNSAFE_HTTP, `Unsafe http requests must be explicitly whitelisted in your configuration (${url.hostname})`);
 
-  const gotOptions: ExtendOptions = {headers, method};
+  const userAgent = `yarn/${YarnVersion ?? 'unknown'} node/${process.versions.node}`;
+  const gotOptions: ExtendOptions = {headers: {['user-agent']: userAgent, ...headers}, method};
   gotOptions.responseType = jsonResponse
     ? `json`
     : `buffer`;