build(deps): bump securesystemslib[crypto,pynacl] from 0.16.0 to 0.17.0

Bumps [securesystemslib[crypto,pynacl]](https://github.com/secure-systems-lab/securesystemslib) from 0.16.0 to 0.17.0.
- [Release notes](https://github.com/secure-systems-lab/securesystemslib/releases)
- [Changelog](https://github.com/secure-systems-lab/securesystemslib/blob/master/CHANGELOG.md)
- [Commits](secure-systems-lab/securesystemslib@v0.16.0...v0.17.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements-pinned.txt

@@ -9,7 +9,7 @@ pycparser==2.20           # via cffi
 pynacl==1.4.0             # via securesystemslib
 python-dateutil==2.8.1    # via securesystemslib
 requests==2.24.0
-securesystemslib[crypto,pynacl]==0.16.0
+securesystemslib[crypto,pynacl]==0.17.0
 six==1.15.0
 subprocess32==3.5.4       ; python_version < '3' # via securesystemslib
 urllib3==1.25.11           # via requests