Description:
Spring Cloud Data Flow supports the ability to allow users to set the version of the app used when launching a task definition.
This is done by using the following property version.<app-name>=<version>.
However when a user schedules a task definition, the format version.<app-name>=<version> does not set the version of the application.
Schedules work on a task definition, so the format to set the app version is version.<task-definition-name>=<version>. While this works it is inconsistent with the usage when launching a task.
So SCDF needs to support the format version.<app-name>=<version>.

Release versions:
Spring Cloud Dataflow 2.11.0 - 2.11.4

Steps to reproduce:

1. Import Task apps
2. Register the 2.0.1 version of timestamp-task
3. Create task definition that contains just the timestamp app.
4. Create schedule for the task definition, but in the properties set the timestamp to user version 2.0.1.

The shell script to reproduce the scenario for Kubernetes is located below:

app register timestamp --type task --uri docker:springcloudtask/timestamp-task:2.0.1
task create ts1 --definition "timestamp"
task schedule create --name w1 --definitionName ts1 --expression '*/1 * * * *' --properties 'version.timestamp=2.0.1'

Additionally
Update reference documentation to show how to set the version when launching and scheduling a task definition.