Automated: Update Podfile.lock (#1371)

Summary:
This is an automated PR to update the Podfile.lock.
- Make sure that the Podfile.lock contains latest FlipperKit and Flipper pod versions.
- Also make sure that all the dependencies are updated to the latest one.
- This is auto-generated by [create-pull-request](https://github.com/peter-evans/create-pull-request)

Pull Request resolved: https://github.com/facebook/flipper/pull/1371

Reviewed By: nikoant

Differential Revision: D22502894

Pulled By: passy

fbshipit-source-id: a9a7fded3fac39810e9cec327be9fb5c3c8e4ef9

Flipper.podspec

@@ -3,7 +3,7 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
-flipperkit_version = '0.49.0'
+flipperkit_version = '0.50.0'
 Pod::Spec.new do |spec|
   spec.name = 'Flipper'
   spec.version = flipperkit_version