refactor: use epoch timestamp

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

shared/lib/Resource/Range/IRangeDate.php

@@ -9,32 +9,30 @@ declare(strict_types=1);
 
 namespace KTXF\Resource\Range;
 
-use DateTimeInterface;
-
 interface IRangeDate extends IRange {
 
 	/**
 	 *
 	 * @since 1.0.0
 	 */
-	public function getStart(): DateTimeInterface;
+	public function getStart(): int;
 
 	/**
 	 *
 	 * @since 1.0.0
 	 */
-	public function setStart(DateTimeInterface $value): void;
+	public function setStart(int $value): void;
 
 	/**
 	 *
 	 * @since 1.0.0
 	 */
-	public function getEnd(): DateTimeInterface;
+	public function getEnd(): int;
 
 	/**
 	 *
 	 * @since 1.0.0
 	 */
-	public function setEnd(DateTimeInterface $value): void;
+	public function setEnd(int $value): void;
 
 }