Update dependency versions

Small breaking type change on return values of DynamoDB library.

Update dependency versions

Small breaking type change on return values of DynamoDB library.

Documentation updates

README update

Docs for multi-entity operations

Also some type cleanup

Updating integration test for condition check

Previous version was occasionally failing when
all tests run.

Next manual chapter - GSIs

BREAKING CHANGE - updates to Store setup

Breaking changes:

* Now only one DynamoDB wrapper / client per store instance
* A whole bunch of changes to store setup and config

Also documentation for setup

The driver for this was that configuration with multiple
DynamoDB clients was messy, and I don't think is that useful. For different clients the user can just instantiate different instances of the entity store.

Support scanning GSI

Doc updates, re-enable NPM publishing