Add IPOs support

[justinpolygon]

Update client with IPOs support. This PR adds a list_ipos function and working example.

$ python3 examples/rest/stocks-ipos.py

[
    IPOListing(
        announced_date=None,
        currency_code="USD",
        final_issue_price=34.0,
        highest_offer_price=34.0,
        ipo_status="history",
        isin="US75734B1008",
        issuer_name="Reddit Inc.",
        last_updated="2024-03-26",
        listing_date="2024-03-21",
        lot_size=None,
        lowest_offer_price=31.0,
        max_shares_offered=22000000,
        min_shares_offered=None,
        primary_exchange="XNYS",
        security_description="Ordinary Shares - Class A",
        security_type="CS",
        shares_outstanding=36871367,
        ticker="RDDT",
        total_offer_size=519401918.0,
        us_code="75734B100",
    )
]

[penelopus]

🐍