distinguish task dependencies: ordering vs resource
distinguish task dependencies: ordering vs resource

there are two types of dependencies between tasks:
- _resource-dependency_: based on resources needed from parent task,
which includes results, workspaces and resources
- _ordering-dependency_: based on runAfter which provides sequencing of
tasks when there may not be resource dependencies

however, it is currently difficult to distinguish between the two

this PR provides a way to know the dependency type and will be useful
for future work such as allowing execution of ordering-dependent tasks
when continueAfterSkip is set to true

tektoncd/pipeline,tektoncd/pipeline