Added some space after markdown headers tags

Added space after `###`, so the hearder could look like markdown header

Author: amadeu01

samples/swift/README.md

@@ -12,16 +12,16 @@ open FirebaseUI-demo-swift.xcworkspace
 ```
 Once you've opened the workspace, go into `Supporting Files/Info.plist` and either fill in the social provider information currently commented out, or delete extra providers you're not interested in. For providers you choose to keep, enable them in your Firebase Dashboard according to the [user authentication docs](https://www.firebase.com/docs/ios/guide/user-auth.html). In `ViewController.m` make sure to only enable providers that you've configured properly.
 
-###Project configuration
+### Project configuration
 
 Please follow steps described [here](https://github.com/firebase/FirebaseUI-iOS#mandatory-sample-project-configuration) in order to run the sample project.
 
-###Chat Sample
+### Chat Sample
 
 This sample uses [anonymous authentication](https://firebase.google.com/docs/auth/ios/anonymous-auth),
 so make sure anonymous auth is enabled in Firebase console.
 
-###Auth Sample
+### Auth Sample
 
 This sample uses [email/password](https://firebase.google.com/docs/auth/ios/password-auth),
 [Google](https://firebase.google.com/docs/auth/ios/google-signin),
@@ -33,7 +33,7 @@ since it depends on the various keys and tokens for the different auth
 services your app will support. Take a look at the [Auth README](../../FirebaseAuthUI/README.md)
 for more information.
 
-###Storage Sample
+### Storage Sample
 
 This sample does not use a logged-in user, so make to set up the [Storage Security Rules](https://firebase.google.com/docs/storage/security/start#sample-rules)
-for your bucket to allow that.
+for your bucket to allow that.