[v5] Remove .onTransition()

[davidkpiano]

This PR removes .onTransition(...) in favor of .subscribe(...)

 const actor = interpret(machine)
-  .onTransition(...)
-  .start();
+actor.subscribe(...);
+actor.start();

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🦋 Changeset detected

Latest commit: ed2562b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
xstate	Major

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