Bump phpseclib/phpseclib in /files/lib/system/api/phpseclib

Bumps [phpseclib/phpseclib](https://github.com/phpseclib/phpseclib) from 3.0.21 to 3.0.36.
- [Release notes](https://github.com/phpseclib/phpseclib/releases)
- [Changelog](https://github.com/phpseclib/phpseclib/blob/master/CHANGELOG.md)
- [Commits](phpseclib/phpseclib@3.0.21...3.0.36)

---
updated-dependencies:
- dependency-name: phpseclib/phpseclib
  dependency-type: direct:production
...

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