added touch support for zoom

inc/js/zoom.js

@@ -29,6 +29,10 @@ function zoom(factor, imgName) {
         moveBackground(getOffsetToMiddle(e));
     });
 
+    img.addEventListener("touchmove", (e) => {
+        moveBackground(getOffsetToMiddle(e));
+    });
+
     img.addEventListener("mouseleave", (e) => {
         img.style.opacity = 1;
     });