Cease to turn commits red based on cargo outdated.
Cease to turn commits red based on cargo outdated.

This was bothersome because it means nearly all commits end up
with a red cross next to them, which harms the signal-to-noise
ratio of the github actions.

I do not want to upgrade to the most recent compatible version:
some users of autocxx have crate trees with hard-coded versions
requirements elsewhere in the tree. Upgrading to the versions
reported by 'cargo outdated' is currently a non-goal; that
would reduce flexibility for those users.

This change also:
* Ceases to report on transitive deps, about which we can do
  nothing; but
* Starts to report on deps of all packages in our workspace.

In an ideal world, 'cargo outdated' would report a failure if
(and only if) there's a new version of a dependency which is not
semver-compatible, but that facility is not currently offered.

google/autocxx,google/autocxx,google/autocxx,google/autocxx