Add Compensation Workflow Pattern Example

Similar to this compensation workflow pattern example in the java sdk, we should have an example of how to do compensation logic in php.

[Here is the example code.](https://github.com/dapr/java-sdk/tree/master/examples/src/main/java/io/dapr/examples/workflows/compensation)
[Here is the readme for it.](https://github.com/dapr/java-sdk/blob/master/examples/src/main/java/io/dapr/examples/workflows/README.md#compensation-pattern)
[Here are the docs for it.](https://github.com/dapr/docs/pull/4665)

We can still improve it after the fact, but we should have a clear example how users can implement this workflow pattern.

We can eventually add something like the following, but in php:
```
ctx.CallActivityWithCompensation(ctx,
"BookFlight", nil,
"CancelFlight", nil)
if err != nil {
// Compensate
return err
}
```

The ask for now is to simply show users how they can implement this pattern in an example.

RELEASE NOTE:
**ADD** Workflow Compensation Pattern Example