SQL::Composer::Update - UPDATE statement
SYNOPSIS
my $expr = SQL::Composer::Update->new(
table => 'table',
values => [a => 'b'],
where => [c => 'd']
);
my $sql = $expr->to_sql; # 'UPDATE `table` SET `a` = ? WHERE `c` = ?'
my @bind = $expr->to_bind; # ['b', 'd']