Add a workspace name based on Bazel guidelines

Change-Id: I387d2530b6fc45b4ab029c29b5387aeba0554a59
Reviewed-on: https://code-review.googlesource.com/5020
Reviewed-by: Paul Wankadia <junyer@google.com>

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 393f5e6..de481fe 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,3 +3,4 @@
 # license that can be found in the LICENSE file.
 
 # Bazel (http://bazel.io/) WORKSPACE file for RE2.
+workspace(name = "com_googlesource_code_re2")