Replace "integer" types with "int", to suppress warnings in PHP 7.4 and PHP 8.0

[jackwh]

Since PHP 7.4, the alias integer can no longer be used as a scalar type. Instead, int must be used. See here for some more info. When loading this package under PHP 8.0, this warning gets thrown in 12 separate places:

PHP Warning:  "integer" will be interpreted as a class name. Did you mean "int"? Write "\LupeCode\phpTraderInterface\integer" or import the class with "use" to suppress this warning in /home/vagrant/my-site/vendor/lupecode/php-trader-interface/source/Trader.php on line 1507

This PR simply replaces the few instances of integer with int... and makes the errors go away.

Thanks for a useful package!

[jb-lopez]

Thanks @jackwh !

[jackwh]

No problem 😊 On a side note, would you consider tagging a new release? The last one seems to be from 2016!

This caught me out at first, I installed with composer require without specifying a version, so it defaulted to the last tag. It took a while before I realised and changed to dev-master. Just in case this catches anyone else out!

[jb-lopez]

I had to manually update Packagist, but it looks okay now. Let me know if you cannot get 1.0.5 from composer.