Bump futures from 0.3.19 to 0.3.21 (#3835)

Bumps [futures](https://github.com/rust-lang/futures-rs) from 0.3.19 to 0.3.21.
- [Release notes](https://github.com/rust-lang/futures-rs/releases)
- [Changelog](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md)
- [Commits](rust-lang/futures-rs@0.3.19...0.3.21)

---
updated-dependencies:
- dependency-name: futures
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Cargo.lock

@@ -30,7 +30,7 @@ async-graphql-warp = "2.9.5"
 base64 = "0.13.0"
 bincode = "1.3.3"
 bech32 = "0.8"
-futures = "0.3.18"
+futures = "0.3.21"
 hex = "0.4"
 jormungandr-lib = { path = "../jormungandr-lib" }
 keynesis = "1.1"

jormungandr/Cargo.toml

@@ -11,7 +11,7 @@ tonic = "0.6"
 prost = "0.9"
 tokio = { version = "1.15", features = ["macros","rt","rt-multi-thread"] }
 tokio-stream = "0.1"
-futures = "0.3.18"
+futures = "0.3.21"
 base64 = "0.13"
 bech32 = "0.8"
 bytesize = "1.1.0"

testing/jormungandr-automation/Cargo.toml

@@ -9,7 +9,7 @@ tonic = "0.6"
 bech32 = "0.7"
 prost = "0.9"
 tokio = { version = "1.15", features = ["macros", "time"] }
-futures      = "0.3.18"
+futures      = "0.3.21"
 base64 = "0.13"
 hex = "0.4.2"
 chain-addr      = { git = "https://github.com/input-output-hk/chain-libs.git", branch = "master" }