proto: merge the proposer-based timestamps parameters

proto/tendermint/types/params.proto

@@ -13,6 +13,7 @@ message ConsensusParams {
   EvidenceParams  evidence  = 2;
   ValidatorParams validator = 3;
   VersionParams   version   = 4;
+  SynchronyParams synchrony = 5;
 }
 
 // BlockParams contains limits on the block size.
@@ -65,3 +66,18 @@ message HashedParams {
   int64 block_max_bytes = 1;
   int64 block_max_gas   = 2;
 }
+
+// SynchronyParams configure the bounds under which a proposed block's timestamp is considered valid.
+// These parameters are part of the proposer-based timestamps algorithm. For more information,
+// see the specification of proposer-based timestamps:
+// https://github.com/tendermint/spec/tree/master/spec/consensus/proposer-based-timestamp
+message SynchronyParams {
+	// message_delay bounds how long a proposal message may take to reach all validators on a newtork
+	// and still be considered valid.
+  google.protobuf.Duration message_delay = 1
+      [(gogoproto.stdduration) = true];
+	// precision bounds how skewed a proposer's clock may be from any validator
+	// on the network while still producing valid proposals.
+  google.protobuf.Duration precision = 2
+      [(gogoproto.stdduration) = true];
+}