(pouchdb/pouchdb#2537) - lock express to 4.6.1
(pouchdb/pouchdb#2537) - lock express to 4.6.1

tyler-johnson/express-pouchdb,nicolasbrugneaux/express-pouchdb,tyler-johnson/express-pouchdb,tyler-johnson/express-pouchdb,nicolasbrugneaux/express-pouchdb,pouchdb/pouchdb-server,pouchdb/pouchdb-server,nicolasbrugneaux/express-pouchdb