Bump futures from 0.3.21 to 0.3.25

Bumps [futures](https://github.com/rust-lang/futures-rs) from 0.3.21 to 0.3.25.
- [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/0.3.21...0.3.25)

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

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

plume-common/Cargo.toml

@@ -24,7 +24,7 @@ activitystreams-ext = "0.1.0-alpha.2"
 url = "2.2.2"
 flume = "0.10.13"
 tokio = { version = "1.19.2", features = ["full"] }
-futures = "0.3.21"
+futures = "0.3.25"
 
 [dependencies.chrono]
 features = ["serde"]