Update due_date in feature test
Update due_date in feature test

due_date = invoice_date + 1 month

levent/openfoodnetwork,openfoodfoundation/openfoodnetwork,ltrls/openfoodnetwork,levent/openfoodnetwork,Em-AK/openfoodnetwork,Em-AK/openfoodnetwork,mkllnk/openfoodnetwork,lin-d-hop/openfoodnetwork,KateDavis/openfoodnetwork,lin-d-hop/openfoodnetwork,RohanM/openfoodnetwork,mkllnk/openfoodnetwork,KateDavis/openfoodnetwork,MikeiLL/openfoodnetwork,openfoodfoundation/openfoodnetwork,levent/openfoodnetwork,oeoeaio/openfoodnetwork,ltrls/openfoodnetwork,Matt-Yorkley/openfoodnetwork,Matt-Yorkley/openfoodnetwork,oeoeaio/openfoodnetwork,Em-AK/openfoodnetwork,MikeiLL/openfoodnetwork,lin-d-hop/openfoodnetwork,oeoeaio/openfoodnetwork,RohanM/openfoodnetwork,oeoeaio/openfoodnetwork,KateDavis/openfoodnetwork,ltrls/openfoodnetwork,mkllnk/openfoodnetwork,mkllnk/openfoodnetwork,openfoodfoundation/openfoodnetwork,Matt-Yorkley/openfoodnetwork,KateDavis/openfoodnetwork,MikeiLL/openfoodnetwork,MikeiLL/openfoodnetwork,lin-d-hop/openfoodnetwork,levent/openfoodnetwork,ltrls/openfoodnetwork,openfoodfoundation/openfoodnetwork,RohanM/openfoodnetwork,Matt-Yorkley/openfoodnetwork,RohanM/openfoodnetwork,Em-AK/openfoodnetwork