fix: error: non-void function does not return a value in all control paths

Author: HeathWang

HWPanModal.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'HWPanModal'
-  s.version          = '0.9.6'
+  s.version          = '0.9.7'
   s.summary          = 'HWPanModal is used to present controller and drag to dismiss.'
 
 # This description is used to generate tags and improve search results.

Sources/View/PanModal/HWPanModalContentView.m

@@ -408,6 +408,7 @@ - (UIView *)findKeyWindow {
             }
         }
     }
+    return nil;
 }
 
 @end