Add e2e tests

vendor/cloud.google.com/go/MIGRATION.md

@@ -0,0 +1,54 @@
+# Code Changes
+
+## v0.10.0
+
+- pubsub: Replace
+
+    ```
+    sub.ModifyPushConfig(ctx, pubsub.PushConfig{Endpoint: "https://example.com/push"})
+    ```
+
+  with
+
+    ```
+    sub.Update(ctx, pubsub.SubscriptionConfigToUpdate{
+        PushConfig: &pubsub.PushConfig{Endpoint: "https://example.com/push"},
+    })
+    ```
+
+- trace: traceGRPCServerInterceptor will be provided from *trace.Client.
+Given an initialized `*trace.Client` named `tc`, instead of
+
+    ```
+    s := grpc.NewServer(grpc.UnaryInterceptor(trace.GRPCServerInterceptor(tc)))
+    ```
+
+  write
+
+    ```
+    s := grpc.NewServer(grpc.UnaryInterceptor(tc.GRPCServerInterceptor()))
+    ```
+
+- trace trace.GRPCClientInterceptor will also provided from *trace.Client.
+Instead of
+
+    ```
+    conn, err := grpc.Dial(srv.Addr, grpc.WithUnaryInterceptor(trace.GRPCClientInterceptor()))
+    ```
+
+  write
+
+    ```
+    conn, err := grpc.Dial(srv.Addr, grpc.WithUnaryInterceptor(tc.GRPCClientInterceptor()))
+    ```
+
+- trace: We removed the deprecated `trace.EnableGRPCTracing`. Use the gRPC
+interceptor as a dial option as shown below when initializing Cloud package
+clients:
+
+    ```
+    c, err := pubsub.NewClient(ctx, "project-id", option.WithGRPCDialOption(grpc.WithUnaryInterceptor(tc.GRPCClientInterceptor())))
+    if err != nil {
+        ...
+    }
+    ```