Adds semantic labels to images and modal close button (#56)

* Added semantic labels to images.

* Reverting project file.

* Semantic label for close button.

veggieseasons/lib/widgets/close_button.dart

@@ -62,6 +62,7 @@ class _ColorChangingIconState
   Widget build(BuildContext context) {
     return Icon(
       widget.icon,
+      semanticLabel: 'Close button',
       size: widget.size,
       color: _colorTween?.evaluate(animation),
     );