simplified running ephemeral Cloud Run environments

[malaskowski]

Description

Simplified action for running ephemeral environments in starter. yaml Cloud Run definition is no longer required.

Motivation and Context

• Faster (time to create) and simpler Cloud Run environments

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue) labeled with bug
• [x] New feature (non-breaking change which adds functionality) labeled with enhancement
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] My code follows the code standards of this project.
• [x] My change requires updating the documentation. I have updated the documentation accordingly.

[github-actions[bot]]

✅ Visual tests status

No visual changes detected.

Name	Link
Commit	92fc32e17810aaf5c3ebd83973275d916f2d6a13
Logs	https://github.com/websight-io/starter/actions/runs/6703753070