[action] add synchronous option to pod_push

[iartemiev]

Checklist

• I've run bundle exec rspec from the root directory to see all new and existing tests pass
• I've followed the fastlane code style and run bundle exec rubocop -a to ensure the code style is valid
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.

Motivation and Context

Updating the pod_push action with a recently-added option.
--synchronous assists developers when deploying multiple interdependent pods to Trunk
CocoaPods PR for context: CocoaPods/cocoapods-trunk#147

Description

Added code to append the option when synchronous: true is passed as a param to the pod_push action.
Augmented the available_options array for the action with the requisite details about the param.

Testing Steps

Added a test for this option to pod_push_spec.rb

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[iartemiev]

The failing CCI job is returning the following error:

/usr/local/Homebrew/Library/Homebrew/brew.rb:10:in `<main>': Homebrew must be run under Ruby 2.6! You're running 2.3.3. (RuntimeError)

Seems to be a CI-related issue...

Edit: scratch that. It seems to have been a transient CI issue. Re-running the pipeline fixed it.

[fastlane-bot]

Hey @iartemiev 👋

Thank you for your contribution to fastlane and congrats on getting this pull request merged 🎉
The code change now lives in the master branch, however it wasn't released to RubyGems yet.
We usually ship about once a week, and your PR will be included in the next one.

Please let us know if this change requires an immediate release by adding a comment here 👍
We'll notify you once we shipped a new release with your changes 🚀

[fastlane-bot]

Congratulations! 🎉 This was released as part of fastlane 2.151.0 🚀