Bump futures-util from 0.3.6 to 0.3.21

Bumps [futures-util](https://github.com/rust-lang/futures-rs) from 0.3.6 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/0.3.6...0.3.21)

---
updated-dependencies:
- dependency-name: futures-util
  dependency-type: indirect
...

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

Cargo.lock

@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "anyhow"
 version = "1.0.33"
@@ -97,9 +99,9 @@ dependencies = [
 
 [[package]]
 name = "futures-channel"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7a4d35f7401e948629c9c3d6638fb9bf94e0b2121e96c3b428cc4e631f3eb74"
+checksum = "c3083ce4b914124575708913bca19bfe887522d6e2e6d0952943f5eac4a74010"
 dependencies = [
  "futures-core",
  "futures-sink",
@@ -107,9 +109,9 @@ dependencies = [
 
 [[package]]
 name = "futures-core"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d674eaa0056896d5ada519900dbf97ead2e46a7b6621e8160d79e2f2e1e2784b"
+checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
 
 [[package]]
 name = "futures-executor"
@@ -124,17 +126,16 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5fc94b64bb39543b4e432f1790b6bf18e3ee3b74653c5449f63310e9a74b123c"
+checksum = "fc4045962a5a5e935ee2fdedaa4e08284547402885ab326734432bed5d12966b"
 
 [[package]]
 name = "futures-macro"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f57ed14da4603b2554682e9f2ff3c65d7567b53188db96cb71538217fc64581b"
+checksum = "33c1e13800337f4d4d7a316bf45a567dbcb6ffe087f16424852d97e97a91f512"
 dependencies = [
- "proc-macro-hack",
  "proc-macro2",
  "quote",
  "syn",
@@ -142,24 +143,21 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0d8764258ed64ebc5d9ed185cf86a95db5cac810269c5d20ececb32e0088abbd"
+checksum = "21163e139fa306126e6eedaf49ecdb4588f939600f0b1e770f4205ee4b7fa868"
 
 [[package]]
 name = "futures-task"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4dd26820a9f3637f1302da8bceba3ff33adbe53464b54ca24d4e2d4f1db30f94"
-dependencies = [
- "once_cell",
-]
+checksum = "57c66a976bf5909d801bbef33416c41372779507e7a6b3a5e25e4749c58f776a"
 
 [[package]]
 name = "futures-util"
-version = "0.3.6"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a894a0acddba51a2d49a6f4263b1e64b8c579ece8af50fa86503d52cd1eea34"
+checksum = "d8b7abd5d659d9b90c8cba917f6ec750a74e2dc23902ef9cd4cc8c8b22e6036a"
 dependencies = [
  "futures-channel",
  "futures-core",
@@ -168,10 +166,8 @@ dependencies = [
  "futures-sink",
  "futures-task",
  "memchr",
- "pin-project",
+ "pin-project-lite",
  "pin-utils",
- "proc-macro-hack",
- "proc-macro-nested",
  "slab",
 ]
 
@@ -293,30 +289,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
 
 [[package]]
-name = "once_cell"
-version = "1.4.1"
+name = "pin-project-lite"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "260e51e7efe62b592207e9e13a68e43692a7a279171d6ba57abd208bf23645ad"
-
-[[package]]
-name = "pin-project"
-version = "0.4.26"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13fbdfd6bdee3dc9be46452f86af4a4072975899cf8592466668620bebfbcc17"
-dependencies = [
- "pin-project-internal",
-]
-
-[[package]]
-name = "pin-project-internal"
-version = "0.4.26"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c82fb1329f632c3552cf352d14427d57a511b1cf41db93b3a7d77906a82dcc8e"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
+checksum = "e0a7ae3ac2f1173085d398531c705756c94a4c56843785df85a60c1a0afac116"
 
 [[package]]
 name = "pin-utils"
@@ -399,9 +375,9 @@ checksum = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 
 [[package]]
 name = "syn"
-version = "1.0.43"
+version = "1.0.67"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e2e59c50ed8f6b050b071aa7b6865293957a9af6b58b94f97c1c9434ad440ea"
+checksum = "6498a9efc342871f91cc2d0d694c674368b4ceb40f62b65a7a08c3792935e702"
 dependencies = [
  "proc-macro2",
  "quote",