v0.21.0 (WARNING: ALPHA SOFTWARE)

This is a breaking release that updates some components of the SDK and its native modules.

In particular:

• Global pool shares have been removed from the staking logic

• NewBaseApp now takes in option functions to set configurable parameters

• NewAccountMapper now takes a constructor function instead of a prototype

• The `--trace-store` option has been added to `gaiad`, which logs all store operations to a file

• IAVL tree pruning is now configurable and enabled by default

See the changelog for complete details:

https://github.com/cosmos/cosmos-sdk/blob/v0.21.0/CHANGELOG.md#0210