(MODULES-11424) Fix requirement method

[Clebam]

This is related to this PR : #283

Having discussed this subject on puppet slack, it is recommended to use require_relative for this purpose.

The problem

require fails to find the path because of concatenation.

The cause

This fix : 2e11fe6
The thing is "Pathname" override the behavior of the "+" sign to handle the missing "/" in the path ( https://ruby-doc.org/stdlib-2.6.3/libdoc/pathname/rdoc/Pathname.html#method-i-2B )

The fix

As mentionned, it is recommended to use require_relative

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[jordanbreen28]

Thanks @Clebam!
Using require_relative is the preferred approach here, I've kicked the tests and lets 👀 what happens