Run iOS jobs on podspec changes (#2136)

Summary:
Updates the run conditions of iOS jobs so that it is triggered when we change "Flipper.podspec" and "FlipperKit.podspec"
## Changelog

- Update the run conditions

Pull Request resolved: https://github.com/facebook/flipper/pull/2136

Test Plan: CI

Reviewed By: passy

Differential Revision: D27402914

Pulled By: priteshrnandgaonkar

fbshipit-source-id: 3b687612f26a0e22773c48540b76a7660bb29ed6

.github/workflows/iOS-Sample.yml

@@ -4,10 +4,14 @@ on:
     paths:
       - "iOS/**"
       - "xplat/**"
+      - "Flipper.podspec"
+      - "FlipperKit.podspec"
   pull_request:
     paths:
       - "iOS/**"
       - "xplat/**"
+      - "Flipper.podspec"
+      - "FlipperKit.podspec"
 
 jobs:
   build-sample-objc: