fixed the base_uri handling inside the rest client
fixed the base_uri handling inside the rest client

jochenmanz/plentymarkets-shopware-connector,plentymarkets/plentymarkets-shopware-connector,pwnyprod/plentymarkets-shopware-connector,ReverseRetail/plentymarkets-shopware-connector,pwnyprod/plentymarkets-shopware-connector,plentymarkets/plentymarkets-shopware-connector,jochenmanz/plentymarkets-shopware-connector,Pfabeck/plentymarkets-shopware-connector,Pfabeck/plentymarkets-shopware-connector,ReverseRetail/plentymarkets-shopware-connector