feat: move to @npmcli/agent

BREAKING CHANGE: this changes the underlying http agents to those
provided by `@npmcli/agent`.  Backwards compatibility should be fully
implemented but due to the scope of this change it was made a breaking
change out of an abundance of caution.

Author: wraithgar

lib/agent.js

@@ -4,7 +4,7 @@ const promiseRetry = require('promise-retry')
 const ssri = require('ssri')
 
 const CachingMinipassPipeline = require('./pipeline.js')
-const getAgent = require('./agent.js')
+const { getAgent } = require('@npmcli/agent')
 const pkg = require('../package.json')
 
 const USER_AGENT = `${pkg.name}/${pkg.version} (+https://npm.im/${pkg.name})`
@@ -14,9 +14,15 @@ const RETRY_ERRORS = [
   'ECONNREFUSED', // remote host refused to open connection
   'EADDRINUSE', // failed to bind to a local port (proxy?)
   'ETIMEDOUT', // someone in the transaction is WAY TOO SLOW
-  'ERR_SOCKET_TIMEOUT', // same as above, but this one comes from agentkeepalive
+  // from @npmcli/agent
+  'ECONNECTIONTIMEOUT',
+  'EIDLETIMEOUT',
+  'ERESPONSETIMEOUT',
+  'ETRANSFERTIMEOUT',
   // Known codes we do NOT retry on:
   // ENOTFOUND (getaddrinfo failure. Either bad hostname, or offline)
+  // EINVALIDPROXY // invalid protocol from @npmcli/agent
+  // EINVALIDRESPONSE // invalid status code from @npmcli/agent
 ]
 
 const RETRY_TYPES = [