ci: create release PR

[jinliu9508]

Description

One Line Summary

Create a workflow to automate the Unity release process.

Testing

• A sample release PR is created by the process in Pull Requests.
• A draft Release is also created by the automate process.
• The release unitypackage is verified to be correct compare to the artifact generated by the manual process.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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This change is 

[fadi-george]

why isnt this in the update-version job i.e. do these steps before create-release pr job?

[fadi-george]

Doesnt seem needed to create a draft release?
I also have shared github release. Example usage:
https://github.com/OneSignal/OneSignal-Cordova-SDK/blob/main/.github/workflows/cd.yml
https://github.com/OneSignal/sdk-actions/blob/main/.github/workflows/github-release.yml

[fadi-george]

Or maybe a separate pr action to run after pr is merged?

[jinliu9508]

The reason I made them together is that I need to copy release notes generated by the shared action to the CHANGELOG inside the Unity project and commit it before release, which is conflicting because the shared action is for after release. I just moved the release part to a separate workflow.

[abdulraqeeb33]

Couldn't look at it closely