Update buildifier version to 3.3.0

Do so based on the merged CI change Iea2fbeeb6.

Change-Id: I3cae64adf2b8c715e268837a9e59d7d87b3737d0
diff --git a/Documentation/dev-contributing.txt b/Documentation/dev-contributing.txt
index b2b9546..512b416 100644
--- a/Documentation/dev-contributing.txt
+++ b/Documentation/dev-contributing.txt
@@ -171,7 +171,7 @@
 link:https://github.com/google/google-java-format[`google-java-format`]
 tool (version 1.7), and to format Bazel BUILD, WORKSPACE and .bzl files the
 link:https://github.com/bazelbuild/buildtools/tree/master/buildifier[`buildifier`]
-tool (version 3.2.1). Unused dependencies are found and removed using the
+tool (version 3.3.0). Unused dependencies are found and removed using the
 link:https://github.com/bazelbuild/buildtools/tree/master/unused_deps[`unused_deps`]
 build tool, a sibling of `buildifier`.