Merge pull request #11050 from meeseeksmachine/auto-backport-of-pr-11048-on-3.1.x

Backport PR #11048 on branch 3.1.x (use path.posix explicitly for URLs)

packages/coreutils/src/url.ts

@@ -2,7 +2,7 @@
 // Distributed under the terms of the Modified BSD License.
 
 import { PartialJSONObject } from '@lumino/coreutils';
-import * as posix from 'path';
+import { posix } from 'path';
 import urlparse from 'url-parse';
 
 /**