build(bazel): revert back to non-vendored yarn in node_repositories() (…

…angular#29034)

Resolves Windows issue bazel-contrib/rules_nodejs#588

PR Close angular#29034

WORKSPACE

@@ -51,7 +51,7 @@ node_repositories(
     node_version = "10.9.0",
     package_json = ["//:package.json"],
     preserve_symlinks = True,
-    vendored_yarn = "@angular//third_party/github.com/yarnpkg/yarn/releases/download:v1.13.0",
+    yarn_version = "1.12.1",
 )
 
 # Setup the angular toolchain which installs npm dependencies into @ngdeps