Minor indentation fix (#267)

Author: kjisoo

Sources/RxDataSources/UI+SectionedViewType.swift

@@ -57,7 +57,7 @@ extension UITableView : SectionedViewType {
         self.reloadSections(indexSet(sections), with: animationStyle)
     }
 
-  public func performBatchUpdates<S>(_ changes: Changeset<S>, animationConfiguration: AnimationConfiguration) {
+    public func performBatchUpdates<S>(_ changes: Changeset<S>, animationConfiguration: AnimationConfiguration) {
         self.beginUpdates()
         _performBatchUpdates(self, changes: changes, animationConfiguration: animationConfiguration)
         self.endUpdates()
@@ -97,7 +97,7 @@ extension UICollectionView : SectionedViewType {
         self.reloadSections(indexSet(sections))
     }
 
-  public func performBatchUpdates<S>(_ changes: Changeset<S>, animationConfiguration: AnimationConfiguration) {
+    public func performBatchUpdates<S>(_ changes: Changeset<S>, animationConfiguration: AnimationConfiguration) {
         self.performBatchUpdates({ () -> Void in
             _performBatchUpdates(self, changes: changes, animationConfiguration: animationConfiguration)
         }, completion: { (completed: Bool) -> Void in