[20190701134654] ECS Task Tags, TLS Version Enforcement

[ddollar]

Notes

• Adds a TaskTags app-level parameter to cause ECS tags to be propagated to the task level.
• Forces TLS 1.2 or above for the Rack API

Pull Requests

• #3272 propagate ecs service tags to tasks [@ddollar]
• #3273 use default http transport for local rack router [@ddollar]
• #3274 update convox/stdapi to force tls 1.2 support [@ddollar]