(#4656) - chore(package): update leveldown to version 1.4.3
(#4656) - chore(package): update leveldown to version 1.4.3

http://greenkeeper.io/

yaronyg/pouchdb,colinskow/pouchdb,TechnicalPursuit/pouchdb,daleharvey/pouchdb,pouchdb/pouchdb,yaronyg/pouchdb,shimaore/pouchdb,garrensmith/pouchdb,bbenezech/pouchdb,willholley/pouchdb,shimaore/pouchdb,jhs/pouchdb,pouchdb/pouchdb,garrensmith/pouchdb,cdaringe/pouchdb,yaronyg/pouchdb,willholley/pouchdb,seigel/pouchdb,seigel/pouchdb,mikeymckay/pouchdb,daleharvey/pouchdb,nickcolley/pouchdb,pouchdb/pouchdb,seigel/pouchdb,daleharvey/pouchdb,lukevanhorn/pouchdb,mikeymckay/pouchdb,lukevanhorn/pouchdb,bbenezech/pouchdb,jhs/pouchdb,willholley/pouchdb,mikeymckay/pouchdb,lukevanhorn/pouchdb,tyler-johnson/pouchdb,cdaringe/pouchdb,tyler-johnson/pouchdb,tyler-johnson/pouchdb,colinskow/pouchdb,nickcolley/pouchdb,cdaringe/pouchdb,TechnicalPursuit/pouchdb,shimaore/pouchdb,nickcolley/pouchdb,TechnicalPursuit/pouchdb,jhs/pouchdb,bbenezech/pouchdb,colinskow/pouchdb,garrensmith/pouchdb