update HISTORY.md

Prep release.

Fixes bchavez#34: Add support for Product.BaseIncrement.

Add support for Product.TradingDisabled.
Add support for MarketData.GetSingleProductAsync.
More XML docs to Coinbase.Pro.Models.Product.
Update HISTORY.md
Update Verify files regarding Product

Update HISTORY.md. Prep v4.0.1.

Change version number to v3.3.0.

Better websocket connection semantics. Re bchavez#18.

Fixed bug in Withdrawals.GetWithdrawal. Used wrong URL path.

Refactoring in ExtensionsForTesting.
Proper acceptance test for Withdrawals.GetWithdrawal

prep release.

Add GetWithdrawal.

prep release.