Upgrade recommended version of buildifier to 3.0.0
Upgrade recommended version of buildifier to 3.0.0

The noteworthy formatting change [1] could be [2], beside the other [3].

Experience should tell soon if/how these warnings may impact buildifier
use within Gerrit.

[1] https://github.com/bazelbuild/buildtools/releases/tag/3.0.0
[2] "Warnings for macro functions without name parameters"
[3] "Improved multi-file analysers"

Change-Id: I299155e0b221845420e296371c3cf80efad1fc80

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