Update dependency bazelbuild/buildtools to latest version
Update dependency bazelbuild/buildtools to latest version

Included changes:

  - 4890966c38b910fd5bd1ad78a3dd88538d09854f Allow FormatString() to work on CommentBlock (#977)

BAZEL_BUILDTOOLS_VERSION_REV_ID: 4890966c38b910fd5bd1ad78a3dd88538d09854f
Change-Id: Ie5e3da371d041d57a18467e810790f8ccf33f14e

google/copybara,google/copybara,google/copybara