Ecs-deploy

- Adding support for loading task definition from file via --task-definition-file
- Updating service now checks task definition for a health check definition to determine if it should wait for RUNNING status or HEALTHY
- Enhanced --run-task with new optional parameters for --wait-for-success, --launch-type, and --network-configuration
- Update Docker image to alpine:3.12

Thanks to majdarbash, nakulpathak3, and maslakov for their contributions!

Includes 194, 200, 202, and 206

This release incorporates a few PRs, special thanks to the contributors:

- kakakakakku for updating Alpine to 3.8
- bobdoah for help with unbound variables
- taka011239 for better Fargate support
- yu-orz for adding executionRoleArn support

--use-latest-task-def Will use the most recently created task definition as it's base, rather than the last used.`