Pin GitHub Actions to full-length commit SHAs - #539

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@6f8efc29b200d32929f49075959781ed54ec270c, actions/checkout@a37ce9120846195fa4ece8f58b268e6043cb2f26. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Unexpected input(s) 'skip_deploy_on_missing_secrets', valid inputs are ['entryPoint', 'args', 'action', 'app_location', 'azure_static_web_apps_api_token', 'api_build_command', 'api_location', 'app_artifact_location', 'output_location', 'app_build_command', 'repo_token', 'routes_location', 'skip_app_build', 'config_file_location', 'skip_api_build', 'production_branch', 'deployment_environment', 'is_static_export', 'data_api_location', 'github_id_token']