Baseline: 1115e526662c041214aecb3b4c9550b91f79275a

Important changes:

  - toolchain type requirements of rules are now treated as implicit
    dependencies in `bazel query`. This includes those defined via
    the `toolchains` parameter of starlark `rule()` definitions.
  - Starlark `min` and `max` buitins now allow a `key` callback,
    similarly to `sorted`.

This release contains contributions from many people at Google, as well as Alexandre Boulgakov, Brentley Jones, Cameron Martin, Emil Waijers, Fabian Meumertzheim, Xdng Yng.