Update Mongoose for Heroku Deployment

[baristikir]

Recently I was facing some issues at deploying the server to Heroku because of type errors inside the built node_modules folder.
These errors were specifically for mongoose but since I have updated the package and removed @types/mongoose (which isn't needed anymore with newer versions) everything worked fine and my build was successful.

https://developer.mongodb.com/community/forums/t/schema-error-while-running-backend-server-nestjs-angular/12440/3

Build Error by Heroku:

Error TS6200 & Error TS2403: Definitions of the following identifiers conflict with those in another file...