m/p/api: use protobuf.Timestamp in LogEntry

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

Change-Id: I937800aa91e86690da0d06f743e720c2d474ad0a
Reviewed-on: https://review.monogon.dev/c/monogon/+/832
Tested-by: Jenkins CI
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/metropolis/proto/api/debug.proto b/metropolis/proto/api/debug.proto
index eabc766..c8deb73 100644
--- a/metropolis/proto/api/debug.proto
+++ b/metropolis/proto/api/debug.proto
@@ -18,6 +18,8 @@
 package metropolis.proto.api;
 option go_package = "source.monogon.dev/metropolis/proto/api";
 
+import "google/protobuf/timestamp.proto";
+
 // NodeDebugService exposes debug and testing endpoints that allow introspection into a running Metropolis node.
 // It is not authenticated and will be disabled in production. It is currently consumed by metropolis/cli/dbg and
 // by tests.
@@ -145,7 +147,7 @@
 message LogEntry {
     message Leveled {
         repeated string lines = 1;
-        int64 timestamp = 2;
+        google.protobuf.Timestamp timestamp = 2;
         LeveledLogSeverity severity = 3;
         string location = 4;
     }
@@ -177,4 +179,4 @@
 message TraceEvent {
     // Currently we do not parse the event data and just return what the kernel outputs, line-by-line.
     string raw_line = 1;
-}
\ No newline at end of file
+}