tsconfig.json exclude setting is not necessary because it is already handled by defaults

[msheakoski]

The exclude setting in tsconfig.json is not necessary because the TypeScript default value already covers the same directories.

https://github.com/nestjs/typescript-starter/blob/08b0150cb67d66a3b5654059ac2c15423ec77764/tsconfig.json#L14

From the TypeScript docs for the exclude setting:

["node_modules", "bower_components", "jspm_packages"], plus the value of outDir if one is specified.

[kamilmysliwiec]

Fixed