Bump futures from 0.3.12 to 0.3.13

Bumps [futures](https://github.com/rust-lang-nursery/futures-rs) from 0.3.12 to 0.3.13.
- [Release notes](https://github.com/rust-lang-nursery/futures-rs/releases)
- [Changelog](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md)
- [Commits](rust-lang/futures-rs@0.3.12...0.3.13)

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

Cargo.toml

@@ -32,14 +32,14 @@ crossbeam-channel = "0.5.0"
 derive_builder = { git = "https://github.com/colin-kiegel/rust-derive-builder" }
 dyn-clone = "1.0.4"
 env_logger = "0.8.3"
-futures = "0.3.12"
+futures = "0.3.13"
 futures-util = "0.3.12"
 getset = "0.1.1"
 ipnetwork = "0.17.0"
 lazy_static = "1.4.0"
 libc = "0.2.86"
 log = { version = "0.4.14", features = ["serde", "std"] }
-nix = "0.19.1"
+nix = "0.20.0"
 notify = { version = "5.0.0-pre.5", features = ["serde"] }
 prost = "0.7.0"
 rmp-serde = "0.15.4"