Seems like an array that is only declared but never assigned to cannot
be dereferenced with `arr[@]` under `set -u`. We can easily work around
this by using an empty string as default value like `:-`.
* Add buildifier targets.
The tool allows to check and format BUILD files in the repo.
To check if files are well formatted, run:
bazel run //:buildifier
To fix badly-formatted files run:
bazel run //:buildifier-fix
* Cleanup dade-copyright-headers formatting.
* Fix dade-copyright-headers on files with just the copyright.
* Run buildifier automatically on CI via 'fmt.sh'.
* Reformat all BUILD files with buildifier.
Excludes autogenerated Bazel files.