chore: release v0.3.0 (#29)

fix: batching (#17)

* fix: segfault on Put or Delete for getTransaction error

* fix: batching

* refactor: cache queries

* fix: use single connection for commit

* fix: use shorter option name

* docs: readme updates

Merge pull request #9 from ipfs/fix/update

Bring up-to-date and test with the datastore test suite