v8.0.0

Changelog

ba49a23 Update CHANGELOG.md for v8.0.0
1d13ba4 Merge pull request #79 from nyaruka/bcast_delete_optimzation
908e189 Only fetch broadcasts which don't have messages
4fd0122 Instead of counting messages left on broadcasts, just check if any exist
bae126e Remove use of deprecated ioutil package
f16a03a Merge pull request #78 from nyaruka/sql_cleanup
91ec410 Update testdb.sql to reflect schema changes and cleanup sql variables
37ef8c5 Update LICENSE
700d5ec Update CI versions
a43ea07 Merge pull request #77 from nyaruka/update_test_deps
789ba79 Test against postgres 14