update WPNUXSecondaryButton to use UIButtonConfiguration API

Author: iamgabrielma

WooCommerce/WordPressAuthenticator/NUX/WPNUXSecondaryButton.m

@@ -1,4 +1,5 @@
 #import "WPNUXSecondaryButton.h"
+#import <UIKit/UIKit.h>
 @import WordPressSharedObjC;
 
 
@@ -31,25 +32,34 @@ - (void)sizeToFit
 
     // Adjust frame to account for the edge insets
     CGRect frame = self.frame;
-    frame.size.width += self.titleEdgeInsets.left + self.titleEdgeInsets.right;
+    frame.size.width += self.configuration.contentInsets.leading + self.configuration.contentInsets.trailing;
     self.frame = frame;
 }
 
 - (CGSize)intrinsicContentSize
 {
     CGSize size = [self sizeThatFits:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX)];
-    size.width += self.titleEdgeInsets.left + self.titleEdgeInsets.right;
+    size.width += self.configuration.contentInsets.leading + self.configuration.contentInsets.trailing;
     return size;
 }
 
 #pragma mark - Private Methods
 
 - (void)configureButton
 {
+    UIButtonConfiguration *config = [UIButtonConfiguration plainButtonConfiguration];
+    config.contentInsets = NSDirectionalEdgeInsetsMake(
+        WPNUXSecondaryButtonTitleEdgeInsets.top,
+        WPNUXSecondaryButtonTitleEdgeInsets.left,
+        WPNUXSecondaryButtonTitleEdgeInsets.bottom,
+        WPNUXSecondaryButtonTitleEdgeInsets.right
+    );
+    self.configuration = config;
+
     self.titleLabel.font = [WPFontManager systemRegularFontOfSize:15.0];
     self.titleLabel.minimumScaleFactor = 10.0/15.0;
     self.titleLabel.adjustsFontSizeToFitWidth = YES;
-    [self setTitleEdgeInsets:WPNUXSecondaryButtonTitleEdgeInsets];
+
     [self setTitleColor:[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0] forState:UIControlStateNormal];
     [self setTitleColor:[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.4] forState:UIControlStateHighlighted];
 }