m/p/common: use protobuf.Timestamp in NodeStatus

This updates NodeStatus to use google.protobuf.Timestamp.
See: issue #129.

Change-Id: I7902908a885a909d5ad6e232333037add5fb02e2
Reviewed-on: https://review.monogon.dev/c/monogon/+/831
Tested-by: Jenkins CI
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/metropolis/proto/common/BUILD.bazel b/metropolis/proto/common/BUILD.bazel
index 45dafd8..21ca6a5 100644
--- a/metropolis/proto/common/BUILD.bazel
+++ b/metropolis/proto/common/BUILD.bazel
@@ -6,6 +6,9 @@
     name = "common_proto",
     srcs = ["common.proto"],
     visibility = ["//metropolis:__subpackages__"],
+    deps = [
+        "@com_google_protobuf//:timestamp_proto",
+    ],
 )
 
 go_proto_library(