Make this bundle able to work with symfony 4

[lukaszwit]

lexik/currency-bundle v2.1.0 requires symfony/framework-bundle ~2.8|~3.0

which makes update to symfony 4 not working

[modstore]

I need this too. Cheers.

[pzienowicz]

+1

[gilles-g]

Hi,
Well we need some times fo test and update. But you are free to propose an PR ;)

[pich]

+1