Update GAX versions for Java (#375)

diff --git a/gapic/packaging/dependencies.yaml b/gapic/packaging/dependencies.yaml
index 3516871..538433b 100644
--- a/gapic/packaging/dependencies.yaml
+++ b/gapic/packaging/dependencies.yaml
@@ -49,7 +49,11 @@
   ruby:
     lower: '0.8.4'
   java:
-    lower: '0.6.1'
+    lower: '1.3.1'
+
+gax_grpc_version:
+  java:
+    lower: '0.20.0'
 
 proto_version:
   python: