Add human readable timestamp in statistic

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/statistics/ReportStatistics.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.gradle.plugin.stat
 import org.jetbrains.kotlin.build.report.metrics.BuildAttribute
 import org.jetbrains.kotlin.build.report.metrics.BuildPerformanceMetric
 import org.jetbrains.kotlin.build.report.metrics.BuildTime
+import java.text.SimpleDateFormat
 
 data class CompileStatData(
     val version: Int = 1,
@@ -22,10 +23,16 @@ data class CompileStatData(
     val kotlinVersion: String = "0.0.0",
     val hostName: String? = "Unset",
     val timeInMillis: Long,
+    val timestamp: String = formatter.format(timeInMillis),
     val nonIncrementalAttributes: Map<BuildAttribute, Int>,
     val timeData: Map<BuildTime, Long>,
     val perfData: Map<BuildPerformanceMetric, Long>
-)
+) {
+    companion object {
+        private val formatter = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
+    }
+}
+
 
 interface ReportStatistics {
     fun report(data: CompileStatData)