Postgres connect error: undefined method `resolve' for Sequel::Postgres::Adapter

[dbackeus]

Environment
MacOS 11.0.1
Latest Ruby 3.0.0-dev installed via rbenv (though the same error occurs with Ruby 3.0.0-rc1)
Using midori-contrib at current HEAD
Using sequel version 5.39.0 (latest official release)

Error
Running Sequel.connect("postgres://...") raises the following exception:

     Failure/Error: resolve.call(get_result)
     
     Sequel::DatabaseConnectionError:
       NameError: undefined local variable or method `resolve' for #<Sequel::Postgres::Adapter:0x00007fae5806ae38 @prepared_statements={}, @db=#<Sequel::Postgres::Database: "postgres://localhost:5432/ci_test">>
       Did you mean?  reset_poll

Backtrace from rspec:

./lib/midori-contrib/sequel/postgres.rb:35:in `block in execute_query_nonblock'
./lib/midori-contrib/sequel/postgres.rb:27:in `execute_query_nonblock'
./lib/midori-contrib/sequel/postgres.rb:22:in `execute_query'
./spec/midori-contrib/postgres_spec.rb:12:in `block (5 levels) in <top (required)>'