Update demo on macOS to use the scale up aspect fit, which is best suitable for thumb degraded image

Author: dreampiggy

Example/SDWebImagePhotosPlugin_Example macOS/TestCollectionViewItem.xib

@@ -20,7 +20,7 @@
                 <imageView horizontalHuggingPriority="251" verticalHuggingPriority="251" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Ouc-ZV-Oxv">
                     <rect key="frame" x="0.0" y="0.0" width="480" height="272"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                    <imageCell key="cell" refusesFirstResponder="YES" alignment="left" imageScaling="proportionallyDown" id="XMf-SK-k5R"/>
+                    <imageCell key="cell" refusesFirstResponder="YES" alignment="left" imageScaling="proportionallyUpOrDown" id="XMf-SK-k5R"/>
                 </imageView>
             </subviews>
             <point key="canvasLocation" x="139" y="154"/>