Update joda-time to 2.9.4

To match the version used in Gerrit.

Change-Id: I6ea9860f193fb45bdede836abae60c868fc86745

lib/BUCK

diff --git a/lib/BUCK b/lib/BUCK
index a3cb2e6..c1fcfe1 100644
--- a/lib/BUCK
+++ b/lib/BUCK
@@ -18,8 +18,8 @@
 
 maven_jar(
   name = 'joda-time',
-  id = 'joda-time:joda-time:2.8',
-  sha1 = '9f2785d7184b97d005a44241ccaf980f43b9ccdb',
+  id = 'joda-time:joda-time:2.9.4',
+  sha1 = '1c295b462f16702ebe720bbb08f62e1ba80da41b',
   exclude = [
     'META-INF/LICENSE.txt',
     'META-INF/NOTICE.txt',