add work with time zones

src/commonTest/kotlin/dev/inmo/krontab/utils/TimeZoneTest.kt

@@ -0,0 +1,23 @@
+package dev.inmo.krontab.utils
+
+import com.soywiz.klock.*
+import dev.inmo.krontab.builder.buildSchedule
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class TimeZoneTest {
+    @Test
+    fun testDifferentTimeZonesReturnsDifferentTimes() {
+        val scheduler = buildSchedule { seconds { every(1) } }
+        val now = DateTime.now()
+        runTest {
+            for (i in 0 .. 24) {
+                val nowTz = now.toOffset(i.hours)
+                val next = scheduler.next(nowTz)!!
+                assertEquals(
+                    (nowTz + 1.seconds).utc.unixMillisLong, next.utc.unixMillisLong
+                )
+            }
+        }
+    }
+}