manifest: android-9.0.0_r37 -> android-9.0.0_r40

* Also, reference the hw/google/pixel project by named tag as opposed
  to an "anonymous" SHA-1 checksum (no change, same ref)

Change-Id: Ib1ea2a1439a2d8fe95d0871139af6f53ed0f8229
1 file changed
tree: ddc69d4668eec5350f1e19aca510981c76e63ed1
  1. snippets/
  2. default.xml
  3. README.mkdn