Bump socket2 from 0.3.17 to 0.3.18 (#803)
Bump socket2 from 0.3.17 to 0.3.18 (#803)

Bumps [socket2](https://github.com/alexcrichton/socket2-rs) from 0.3.17 to 0.3.18.
- [Release notes](https://github.com/alexcrichton/socket2-rs/releases)
- [Commits](https://github.com/alexcrichton/socket2-rs/commits)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
alex/ct-tools,alex/ct-tools