Remove redundant $ symbol in google-cloudrun-docker.yml

[hellohawaii]

Fix a bug in google-cloudrun-docker.yml.

When defining the DOCKER_TAG variable, an extra dollar sign ($) was incorrectly prepended to the ${{ env.REGION }} expression. This caused the shell to misinterpret the variable during expansion.

Specifically, when env.REGION was set to us-central1-c, the shell attempted to expand $us-central1-c. Because the variable $us was undefined, it was replaced with an empty string, resulting in a malformed image tag that started with -central1-c.cThis tag format is invalid according to Docker's naming conventions, which caused the build step to fail.

[Copilot]

Pull Request Overview

This PR fixes a shell variable expansion bug in the Google Cloud Run Docker deployment workflow where an extra dollar sign was causing incorrect tag generation.

• Removes redundant $ symbol from the DOCKER_TAG variable definition
• Prevents shell misinterpretation of GitHub Actions environment variable expansion
• Ensures proper Docker image tag format for Cloud Run deployments

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