Bump lib/CPP_PTB from fdbbfdf to 378dcd8

Bumps [lib/CPP_PTB](https://github.com/cpp-lln-lab/CPP_PTB) from `fdbbfdf` to `378dcd8`.
- [Release notes](https://github.com/cpp-lln-lab/CPP_PTB/releases)
- [Commits](cpp-lln-lab/CPP_PTB@fdbbfdf...378dcd8)

---
updated-dependencies:
- dependency-name: lib/CPP_PTB
  dependency-type: direct:production
...

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