Bump openssl from 0.10.59 to 0.10.60 in /cmd/pinniped-proxy

Bumps [openssl](https://github.com/sfackler/rust-openssl) from 0.10.59 to 0.10.60.
- [Release notes](https://github.com/sfackler/rust-openssl/releases)
- [Commits](sfackler/rust-openssl@openssl-v0.10.59...openssl-v0.10.60)

---
updated-dependencies:
- dependency-name: openssl
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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