Update dependencies

[Sarah Coxon]

Hi,

Would there be any chance of updating the dependencies for both stdlib and concat as we would like to use your module but we have version 5.2 installed for both of these and your dependencies are less than 5

Thanks,
Sarah

[Louis VICAINNE]

Hello !
I let you propose the PR and I will merge it :)
I'm using an older version on my side but I understand your need :)
Kr