Add feature getGap

Author: Skyline-23

Sources/Swift/FlexLayout.swift

@@ -1217,6 +1217,18 @@ public final class Flex {
     // MARK: Gap
     //
 
+    /**
+     Get paddings between views.
+    */
+    @discardableResult
+    public func getGap(_ gutter: Gutter) -> CGFloat {
+        switch gutter {
+        case .column:   return yoga.columnGap
+        case .row:      return yoga.rowGap
+        case .all:      return yoga.gap
+        }
+    }
+
     /**
      Set paddings between views.
     */