Baseline: b48a319187c87e230b59142b4f7366775173faf4

Important changes:

  - Changes to environment variables read via `getenv` now correctly
    invalidate module extensions.
  - `--experimental_collect_system_network_usage` is flipped to
    `true`.
  - Progress is no longer written to BEP after the build completing
    event is posted.

This release contains contributions from many people at Google, as well as Alessandro Patti, dependabot[bot], Fabian Meumertzheim, Keith Smiley, Matt Smith, Xdng Yng.