bump @nestjs/common, knex and pg to latest versions

[tmarkovic]

Not entirely sure how dependabot works but there seems to be incompatibilities with either nestjs/common, knex or pg.

Tested with postgresql 11.5, nestjs/common 7.1

[miso-belica]

Duplicate to https://github.com/nestjsplus/knex/pull/14#issuecomment-864990110