He probably did share what he had learned
I don't think there is ever an explicit mention of Peter Pettigrew telling Voldemort information he picked up about Harry, but it seems likely that he would have, based on several factors.
He shared other information
We know that he told Voldemort other information that he had picked up over the years of Voldemort's exile. When Voldemort rebukes the Death Eaters in the graveyard at the end of Goblet of Fire he says:
"Macnair... destroying dangerous beasts for the Ministry of Magic now,
Wormtail tells me.
He didn't care about Harry
One might suppose that Pettigrew would refrain from giving Voldemort information in order to help Harry, but Pettigrew himself tells Voldemort in the beginning of Goblet of Fire that he does not care about Harry:
"My Lord, I do not say this out of concern for the boy!" said
Wormtail, his voice rising squeakily. "The boy is nothing to me,
nothing at all!
While this is something that one would say even if it wasn't true, and indeed Voldemort accuses him of lying in that very scene, I don't see evidence that he was lying about that specific point.
He could use the extra value it would give him
Additionally, Pettigrew needed every possible way to curry favor with Voldemort. Throughout the time that he attended Voldemort, Voldemort repeatedly mocked his incompetence and wavering loyalty. If Pettigrew had any valuable information it would certainly add to his usefulness if he shared it with Voldemort. We know, for instance, that Voldemort was particularly pleased with all the information Snape was able to provide him from his years in Hogwarts, as Snape informs Bellatrix in the begining of Half-Blood Prince:
"Hardly," said Snape "although the Dark Lord is pleased that I never
deserted my post: I had sixteen years of information on Dumbledore to
give him when he returned, a rather more useful welcome-back present
than endless reminiscences of how unpleasant Azkaban is..."
Sirius assumed that he had divulged information
Additionally, we know that Sirius assumed that Pettigrew had in fact told Voldemort about Sirius's animagus form, as Sirius tells Harry in the beginning of Order of the Phoenix:
"Because the Ministry of Magic's still after me, and Voldemort will
know all about me being an animagus by now, Wormtail will have told
him, so my big disguise is useless.
We also know from later in Order of the Phoenix when Sirius and Snape got into an argument over Christmas that Lucius Malfoy recognized Sirius's dog form, so that likely confirms that Pettigrew did share the information:
“Speaking of dogs,” said Snape softly, “did you know that Lucius
Malfoy recognized you last time you risked a little jaunt outside?
Clever idea, Black, getting yourself seen on a safe station platform...
gave you a cast-iron excuse not to leave your hideyhole in future,
We can assume that if Pettigrew told Voldemort about Sirius, he probably also told him about Harry as well.
There probably wasn't much to tell
Even assuming Pettigrew did share the information he had picked up, it probably wasn't very much. Harry didn't have very many secrets worth telling. Most things about him (e.g. that he was good at flying, or who his friends were) were probably well known, and most other information would probably not be very useful. Pettigrew might have known a few things, such as that Harry had an Invisibilty Cloak and the Marauders Map, but even that would be of limited use to Voldemort. The one time that we know that Voldemort needed personal information about Harry, Pettigrew was apparently unable to provide it and Voldemort got it from Kreacher instead, as Dumbledore told Harry after the battle at the Ministry in *Order of the Phoenix:
“Oh yes,” said Dumbledore. “You see, Kreacher was not able to betray
us totally. He is not Secret-Keeper for the Order, he could not give
the Malfoys our whereabouts or tell them any of the Order’s
confidential plans that he had been forbidden to reveal. He was bound
by the enchantments of his kind, which is to say that he could not
disobey a direct order from his master, Sirius. But he gave Narcissa
information of the sort that is very valuable to Voldemort, yet must
have seemed much too trivial for Sirius to think of banning him from
“Like what?” said Harry.
“Like the fact that the person Sirius cared most about in the world
was you,” said Dumbledore quietly. “Like the fact that you were coming
to regard Sirius as a mixture of father and brother. Voldemort knew
already, of course, that Sirius was in the Order, that you knew where
he was — but Kreacher’s information made him realize that the one
person whom you would go to any lengths to rescue was Sirius Black.”
Indeed, this information, like most of the important things about Harry that pertained to Voldemort, was not even known to Harry at the time that Pettigrew was impersonating Scabbers.