Bump libc from 0.2.77 to 0.2.78

Bumps [libc](https://github.com/rust-lang/libc) from 0.2.77 to 0.2.78.
- [Release notes](https://github.com/rust-lang/libc/releases)
- [Commits](rust-lang/libc@0.2.77...0.2.78)

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

Author: dependabot[bot]

Cargo.lock

@@ -35,7 +35,7 @@ tokio = { version = "0.2.22", features = ["full"] }
 ansi_term = "0.12"
 
 [target.'cfg(target_os = "linux")'.dependencies]
-libc = "0.2.77"
+libc = "0.2.78"
 base64 = "0.13.0"
 
 [dev-dependencies]