Log Message:
Update ruby-mysql2 to 0.4.5.

0.4.5

New Features

    * Add new connection argument :ssl_mode to Mysql2::Client#new
    * Prepared statements now support DateTime arguments

Bugfixes

    * Fix segfault when wrapper->result is used after it is freed
    * Raise an exception but don't crash on non-string encoding argument
    * Raise an exception but don't crash on nil argument to Mysql2::Client#new
    * Avoid RangeError on integers larger than LONG_LONG
    * Fix a BigDecimal value binding in Prepared Statements
    * Avoid type error when using connect_timeout, read_timeout and
      write_timeout in a DATABASE_URL env variable

Changes

    * Travis CI matrix now includes MySQL 8.0
    * Travis CI matrix defaults to MySQL 5.6
    * AppVeyor CI matrix switched to MySQL 5.7
    * Fix test that implicitly creates a passwordless user
    * Use RSpec expect output instead of StringIO
    * Move macro REQUIRE_CONNECTED to client.c
    * Add a note about casting boolean columns
    * Suppress rubocop's invalid UTF-8 literal warning