Fix watchOS Example Podfile referencing non-existent branch

examples/watchOS Example/Podfile

 use_frameworks!
 
 target 'watchOSsample' do
-pod 'Alamofire', :git => 'git@github.com:neonichu/Alamofire.git', :branch => 'watchos'
+pod 'Alamofire', '~> 2.0.0-beta.1'
 end
 
 target 'watchOSsample WatchKit Extension' do
 platform :watchos, '2.0'
-pod 'Alamofire', :git => 'git@github.com:neonichu/Alamofire.git', :branch => 'watchos'
+pod 'Alamofire', '~> 2.0.0-beta.1'
 end