Use parse_rfc3339() in the tor-rtmock crate

Cargo.lock

@@ -4133,6 +4133,7 @@ dependencies = [
  "async-trait",
  "futures",
  "futures-await-test",
+ "humantime 2.1.0",
  "pin-project",
  "rand 0.8.5",
  "thiserror",

crates/tor-rtmock/Cargo.toml

@@ -14,6 +14,7 @@ repository = "https://gitlab.torproject.org/tpo/core/arti.git/"
 [dependencies]
 async-trait = "0.1.2"
 futures = "0.3.14"
+humantime = "2"
 pin-project = "1"
 thiserror = "1"
 tor-rtcompat = { version = "0.8.0", path = "../tor-rtcompat" }

crates/tor-rtmock/tests/rtcompat_timing.rs

@@ -60,8 +60,8 @@ fn timeouts() {
 }
 
 fn start() -> SystemTime {
-    // Yes this is a homestuck reference
-    SystemTime::UNIX_EPOCH + Duration::from_secs(1239657180)
+    use humantime::parse_rfc3339;
+    parse_rfc3339("2009-04-13T09:13:00Z").unwrap()
 }
 const ONE_DAY: Duration = Duration::from_secs(86400);