Bump nx from 17.3.0 to 19.6.1

Bumps [nx](https://github.com/nrwl/nx/tree/HEAD/packages/nx) from 17.3.0 to 19.6.1.
- [Release notes](https://github.com/nrwl/nx/releases)
- [Commits](https://github.com/nrwl/nx/commits/19.6.1/packages/nx)

---
updated-dependencies:
- dependency-name: nx
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>