chore(deps): bump pynacl from 1.3.0 to 1.4.0 (#320)

Bumps [pynacl](https://github.com/pyca/pynacl) from 1.3.0 to 1.4.0.
- [Release notes](https://github.com/pyca/pynacl/releases)
- [Changelog](https://github.com/pyca/pynacl/blob/master/CHANGELOG.rst)
- [Commits](pyca/pynacl@1.3.0...1.4.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>