feat(protocol_upgrade) - implemented multiple protocol version upgrad…

…es in one release (near#11368)

Implemented the feature described in near#10911. 

It may or may not be needed for the congestion control and stateless
validation release but it should be useful in general and I just want to
take this variable out of the equation.

chain/client/src/metrics.rs

@@ -361,10 +361,11 @@ pub(crate) static CURRENT_PROTOCOL_VERSION: Lazy<IntGauge> = Lazy::new(|| {
         .unwrap()
 });
 
-pub(crate) static NODE_PROTOCOL_UPGRADE_VOTING_START: Lazy<IntGauge> = Lazy::new(|| {
-    try_create_int_gauge(
+pub(crate) static NODE_PROTOCOL_UPGRADE_VOTING_START: Lazy<IntGaugeVec> = Lazy::new(|| {
+    try_create_int_gauge_vec(
         "near_node_protocol_upgrade_voting_start",
-        "Time in seconds since Unix epoch determining when node will start voting for the protocol upgrade; zero if there is no schedule for the voting")
+        "Time in seconds since Unix epoch determining when node will start voting for the protocol upgrade; zero if there is no schedule for the voting",
+     &["protocol_version"])
         .unwrap()
 });
 
@@ -404,8 +405,12 @@ pub(crate) static PRODUCE_AND_DISTRIBUTE_CHUNK_TIME: Lazy<HistogramVec> = Lazy::
 /// `neard_version` argument.
 pub(crate) fn export_version(neard_version: &near_primitives::version::Version) {
     NODE_PROTOCOL_VERSION.set(near_primitives::version::PROTOCOL_VERSION.into());
-    NODE_PROTOCOL_UPGRADE_VOTING_START
-        .set(near_primitives::version::PROTOCOL_UPGRADE_SCHEDULE.timestamp());
+    let schedule = near_primitives::version::PROTOCOL_UPGRADE_SCHEDULE;
+    for (datetime, protocol_version) in schedule.schedule().iter() {
+        NODE_PROTOCOL_UPGRADE_VOTING_START
+            .with_label_values(&[&protocol_version.to_string()])
+            .set(datetime.timestamp());
+    }
     NODE_DB_VERSION.set(near_store::metadata::DB_VERSION.into());
     NODE_BUILD_INFO.reset();
     NODE_BUILD_INFO