Change shebang to "#!/usr/bin/env python3" in python shell scripts. Related to...

hived/get_ops_in_block.py

hived/reference/account_by_key_api/get_key_references.py

hived/reference/account_history_api/enum_virtual_ops.py

hived/reference/account_history_api/get_account_history.py

hived/reference/account_history_api/get_ops_in_block.py

hived/reference/account_history_api/get_transaction.py

hived/reference/condenser_api/broadcast_block.py

hived/reference/condenser_api/broadcast_transaction.py

...erence/condenser_api/broadcast_transaction_synchronous.py

hived/reference/condenser_api/find_proposals.py

hived/reference/condenser_api/get_account_count.py

hived/reference/condenser_api/get_account_history.py

hived/reference/condenser_api/get_active_witnesses.py

hived/reference/condenser_api/get_block.py

hived/reference/condenser_api/get_block_header.py

hived/reference/condenser_api/get_chain_properties.py

hived/reference/condenser_api/get_config.py

hived/reference/condenser_api/get_conversion_requests.py

...ference/condenser_api/get_current_median_history_price.py

.../reference/condenser_api/get_dynamic_global_properties.py