Add support for repeated timestamps and durations to to_dict from_dict (#211)

tests/inputs/repeated_duration_timestamp/repeated_duration_timestamp.json

@@ -0,0 +1,4 @@
+{
+    "times": ["1972-01-01T10:00:20.021Z", "1972-01-01T10:00:20.021Z"],
+    "durations": ["1.200s", "1.200s"]
+}

tests/inputs/repeated_duration_timestamp/repeated_duration_timestamp.proto

@@ -0,0 +1,10 @@
+syntax = "proto3";
+
+import "google/protobuf/duration.proto";
+import "google/protobuf/timestamp.proto";
+
+
+message Test {
+    repeated google.protobuf.Timestamp times = 1;
+    repeated google.protobuf.Duration durations = 2;
+}

tests/inputs/repeated_duration_timestamp/test_repeated_duration_timestamp.py

@@ -0,0 +1,9 @@
+from datetime import datetime, timedelta
+
+from tests.output_betterproto.repeated_duration_timestamp import Test
+
+
+def test_roundtrip():
+    message = Test()
+    message.times = [datetime.now(), datetime.now()]
+    message.durations = [timedelta(), timedelta()]