Add support for --force-upgrade-to-af3 flag in deploy-action

[bmanan7]

Description

Currently, the out-of-the-box astronomer/deploy-action does not provide a way to pass the --force-upgrade-to-af3 flag when running astro deploy. This flag is required for in-place upgrades from Airflow 2 to Airflow 3 (per the Astronomer docs
).

Problem

Teams that standardize on GitHub Actions for deploying to Astronomer cannot currently perform the AF2 --> AF3 upgrade fully within their existing pipelines. This forces them to either:

Run the upgrade manually with the Astro CLI outside their CI/CD flow, or
Copy the action logic and customize it themselves.

Suggested Implementation

Add a new optional input, disabled by default, that conditionally appends the flag to astro deploy commands.