Bump pynacl from 1.3.0 to 1.4.0

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](https://github.com/pyca/pynacl/compare/1.3.0...1.4.0)

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

requirements-indirect.txt

@@ -17,7 +17,7 @@ py==1.9.0
 pycodestyle==2.6.0
 pycparser==2.20
 pyflakes==2.2.0
-PyNaCl==1.3.0
+PyNaCl==1.4.0
 pyparsing==2.4.7
 pyrsistent==0.16.0
 smmap==3.0.4