Read Buildifier version from env variables. (#541)
Read Buildifier version from env variables. (#541)

buildifier.py will download and use the version of Buildifier that is
specified in the BUILDIFIER_VERSION environment variable.
If this variable is not specified, the script continues to use the
Buildifier binary that is part of the Docker image.

https://github.com/bazelbuild/continuous-integration/issues/530

bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration