add missed properties to tasks.schema.json (#641)
add missed properties to tasks.schema.json (#641)

* add missed properties to tasks.schema.json

* Update tasks.schema.json

* Update tasks.schema.json

* Update tasks.schema.json
Microsoft/vsts-task-lib,Microsoft/vsts-task-lib,Microsoft/vsts-task-lib,Microsoft/vsts-task-lib,Microsoft/vsts-task-lib