Bug 1783101 - update zlib 1.2.11 url. r=taskgraph-reviewers,releng-reviewers,ahal DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D153780

taskcluster/ci/fetch/toolchains.yml

@@ -186,7 +186,7 @@ zlib-1.2.11:
     description: zlib 1.2.11 source code
     fetch:
         type: static-url
-        url: http://zlib.net/zlib-1.2.11.tar.gz
+        url: https://downloads.sourceforge.net/project/libpng/zlib/1.2.11/zlib-1.2.11.tar.gz
         sha256: c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1
         size: 607698
         gpg-signature: