build(deps): bump futures-sink from 0.3.7 to 0.3.8

Bumps [futures-sink](https://github.com/rust-lang/futures-rs) from 0.3.7 to 0.3.8.
- [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/0.3.7...0.3.8)

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

Cargo.lock

@@ -471,9 +471,9 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.7"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e3ca3f17d6e8804ae5d3df7a7d35b2b3a6fe89dac84b31872720fc3060a0b11"
+checksum = "f878195a49cee50e006b02b93cf7e0a95a38ac7b776b4c4d9cc1207cd20fcb3d"
 
 [[package]]
 name = "futures-task"