update sequelize, sequelize-typescript version

[m00n620]

This will close #9271

[m00n620]

@searchableguy , It will be better to create types instead of using infer attributes. We need to handle strict types.

[m00n620]

I think you have changed some of the constrains. Would you be able to make sure this does not change?

@julien51 , to use sequelize v6 upsert, we need unique constraints. I think current version is working well.

[searchableguy]

Hm, I'm not sure they add more value here since you will be declaring types again on the class in the same file anyway. Inferring from that allow us to have single source of truth and sequelize typescript page has explicit utilities so that's a supported path.

I would use the infer utilities here and make sure class type declarations reflect schema.