Update gNMI version and build script

Change-Id: I0f2d3c84a7a13111dc5da966b21836338d327929
diff --git a/WORKSPACE b/WORKSPACE
index 723f0ac..1e83aaa 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -68,6 +68,10 @@
 
 generate_p4lang()
 
+load("//tools/build/bazel:gnmi_workspace.bzl", "generate_gnmi")
+
+generate_gnmi()
+
 git_repository(
     name = "build_bazel_rules_nodejs",
     remote = "https://github.com/bazelbuild/rules_nodejs.git",