Bazel: Replace deprecated auth_enabled option

This option is deprecated and should be replaced with:
--google_default_credentials option.

Change-Id: Ie6a93954f33f009aa0c16d1badd7ab4cb7017a91

tools/remote-bazelrc

diff --git a/tools/remote-bazelrc b/tools/remote-bazelrc
index bbfe3a8..78b86d2 100644
--- a/tools/remote-bazelrc
+++ b/tools/remote-bazelrc
@@ -57,7 +57,7 @@
 # Enable authentication. This will pick up application default credentials by
 # default. You can use --auth_credentials=some_file.json to use a service
 # account credential instead.
-build:remote --auth_enabled=true
+build:remote --google_default_credentials
 
 # The following flags enable the remote cache so action results can be shared
 # across machines, developers, and workspaces.