Bump libgit2-sys in /examples/restriction/question_mark_in_expression

Bumps [libgit2-sys](https://github.com/rust-lang/git2-rs) from 0.13.4+1.4.2 to 0.13.5+1.4.5.
- [Release notes](https://github.com/rust-lang/git2-rs/releases)
- [Commits](rust-lang/git2-rs@libgit2-sys-0.13.4...libgit2-sys-0.13.5)

---
updated-dependencies:
- dependency-name: libgit2-sys
  dependency-type: indirect
...

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

Author: dependabot[bot]