Bump phpseclib/phpseclib from 3.0.20 to 3.0.39 in /pets-api

Bumps [phpseclib/phpseclib](https://github.com/phpseclib/phpseclib) from 3.0.20 to 3.0.39.
- [Release notes](https://github.com/phpseclib/phpseclib/releases)
- [Changelog](https://github.com/phpseclib/phpseclib/blob/master/CHANGELOG.md)
- [Commits](phpseclib/phpseclib@3.0.20...3.0.39)

---
updated-dependencies:
- dependency-name: phpseclib/phpseclib
  dependency-type: indirect
...

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