repo: update to 2.5 launcher

Bug: None
Test: `repo sync` still works
Change-Id: I472e5f8753f96f1ad45c9782e4ac30b71a620ab5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2120252Reviewed-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>