Adding support for TLS connections for gRPC clients

This patch uses BoringSSL to negotiate TLS sessions under the hood.

Change-Id: I1495479ff33654f9cffe04d61f293c3e923b8aeb
diff --git a/lib/deps.json b/lib/deps.json
index 06fedf4..1535dc7 100644
--- a/lib/deps.json
+++ b/lib/deps.json
@@ -240,6 +240,7 @@
     "io_netty_netty_codec-http2": "mvn:io.netty:netty-codec-http2:4.1.32.Final",
     "io_netty_netty_codec-http": "mvn:io.netty:netty-codec-http:4.1.32.Final",
     "io_netty_netty_codec-socks": "mvn:io.netty:netty-codec-socks:4.1.32.Final",
+    "io_netty_netty_tcnative_boringssl": "mvn:io.netty:netty-tcnative-boringssl-static:2.0.20.Final",
     "objenesis": "mvn:org.objenesis:objenesis:2.6",
     "openflowj": "mvn:org.onosproject:openflowj:3.2.1.onos",
     "org.osgi.util.function": "mvn:org.osgi:org.osgi.util.function:1.1.0",