dev-contributing: Specify the version of buildifier to use

The latest released version of buildifier is 0.4.5.

Change-Id: Ic6ac567ae12e584525c539b43240601e0c3d4c38

Documentation/dev-contributing.txt

diff --git a/Documentation/dev-contributing.txt b/Documentation/dev-contributing.txt
index 823424e..405b1d7 100644
--- a/Documentation/dev-contributing.txt
+++ b/Documentation/dev-contributing.txt
@@ -154,8 +154,8 @@
 To format Java source code, Gerrit uses the
 link:https://github.com/google/google-java-format[`google-java-format`]
 tool (version 1.3), and to format Bazel BUILD and WORKSPACE files the
-link:https://github.com/bazelbuild/buildifier[`buildifier`] tool. These
-tools automatically apply format according to the style guides; this
+link:https://github.com/bazelbuild/buildifier[`buildifier`] tool (version 0.4.5).
+These tools automatically apply format according to the style guides; this
 streamlines code review by reducing the need for time-consuming, tedious,
 and contentious discussions about trivial issues like whitespace.