bump some version

Elliotte Harold · Elliotte Harold · commit da780702593d · 2018-09-26T14:23:36.000-04:00
diff --git a/google-cloud-clients/pom.xml b/google-cloud-clients/pom.xml
@@ -158,7 +158,7 @@
     <api-client.version>1.24.1</api-client.version>
     <gax.version>1.31.0</gax.version>
     <google.auth.version>0.11.0</google.auth.version>
-    <grpc.version>1.13.1</grpc.version>
+    <grpc.version>1.15.0</grpc.version>
     <nettyssl.version>2.0.7.Final</nettyssl.version>
     <guava.version>20.0</guava.version>
     <http-client.version>1.24.1</http-client.version>
