chore(deps): bump futures-executor from 0.3.19 to 0.3.21 (#873)

Bumps [futures-executor](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](https://github.com/rust-lang/futures-rs/compare/0.3.19...0.3.21)

---
updated-dependencies:
- dependency-name: futures-executor
  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>

Cargo.lock

@@ -1548,9 +1548,9 @@ dependencies = [
 
 [[package]]
 name = "futures-channel"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ba3dda0b6588335f360afc675d0564c17a77a2bda81ca178a4b6081bd86c7f0b"
+checksum = "c3083ce4b914124575708913bca19bfe887522d6e2e6d0952943f5eac4a74010"
 dependencies = [
  "futures-core",
  "futures-sink",
@@ -1558,15 +1558,15 @@ dependencies = [
 
 [[package]]
 name = "futures-core"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0c8ff0461b82559810cdccfde3215c3f373807f5e5232b71479bff7bb2583d7"
+checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
 
 [[package]]
 name = "futures-executor"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "29d6d2ff5bb10fb95c85b8ce46538a2e5f5e7fdc755623a7d4529ab8a4ed9d2a"
+checksum = "9420b90cfa29e327d0429f19be13e7ddb68fa1cccb09d65e5706b8c7a749b8a6"
 dependencies = [
  "futures-core",
  "futures-task",
@@ -1575,15 +1575,15 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1f9d34af5a1aac6fb380f735fe510746c38067c5bf16c7fd250280503c971b2"
+checksum = "fc4045962a5a5e935ee2fdedaa4e08284547402885ab326734432bed5d12966b"
 
 [[package]]
 name = "futures-macro"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6dbd947adfffb0efc70599b3ddcf7b5597bb5fa9e245eb99f62b3a5f7bb8bd3c"
+checksum = "33c1e13800337f4d4d7a316bf45a567dbcb6ffe087f16424852d97e97a91f512"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1592,15 +1592,15 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3055baccb68d74ff6480350f8d6eb8fcfa3aa11bdc1a1ae3afdd0514617d508"
+checksum = "21163e139fa306126e6eedaf49ecdb4588f939600f0b1e770f4205ee4b7fa868"
 
 [[package]]
 name = "futures-task"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ee7c6485c30167ce4dfb83ac568a849fe53274c831081476ee13e0dce1aad72"
+checksum = "57c66a976bf5909d801bbef33416c41372779507e7a6b3a5e25e4749c58f776a"
 
 [[package]]
 name = "futures-timer"
@@ -1610,9 +1610,9 @@ checksum = "e64b03909df88034c26dc1547e8970b91f98bdb65165d6a4e9110d94263dbb2c"
 
 [[package]]
 name = "futures-util"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b5cf40b47a271f77a8b1bec03ca09044d99d2372c0de244e66430761127164"
+checksum = "d8b7abd5d659d9b90c8cba917f6ec750a74e2dc23902ef9cd4cc8c8b22e6036a"
 dependencies = [
  "futures-channel",
  "futures-core",