Ethereum-etl

Add Python 3.8 support

https://hub.docker.com/r/blockchainetl/ethereum-etl/tags

- Add item_timestamp to streaming output for all entities.
- Add item_timestamp attribute to PubSub output for all entities.

Add support for Postgres to `stream` command:

bash
ethereumetl stream --start-block 500000 --output postgresql+pg8000://<user>:<password><host>:5432/<database>


https://ethereum-etl.readthedocs.io/en/latest/commands/#stream

Added trace_id to traces export

Added `ethereumetl stream` command https://github.com/blockchain-etl/ethereum-etl#stream