chore(deps): bump the rust-dependencies group with 3 updates

Updates the requirements on [base64](https://github.com/marshallpierce/rust-base64), [metrics](https://github.com/metrics-rs/metrics) and [proptest-derive](https://github.com/proptest-rs/proptest) to permit the latest version.

Updates `base64` to 0.21.7
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/rust-base64@v0.13.1...v0.21.7)

Updates `metrics` to 0.21.1
- [Changelog](https://github.com/metrics-rs/metrics/blob/main/release.toml)
- [Commits](metrics-rs/metrics@metrics-v0.21.1...metrics-v0.21.1)

Updates `proptest-derive` to 0.3.0
- [Release notes](https://github.com/proptest-rs/proptest/releases)
- [Changelog](https://github.com/proptest-rs/proptest/blob/master/CHANGELOG.md)
- [Commits](proptest-rs/proptest@proptest-derive-0.3.0...proptest-derive-0.3.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
  dependency-group: rust-dependencies
- dependency-name: metrics
  dependency-type: direct:production
  dependency-group: rust-dependencies
- dependency-name: proptest-derive
  dependency-type: direct:production
  dependency-group: rust-dependencies
...

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

Cargo.toml

@@ -119,20 +119,20 @@ members = ["lurk-macros", "lurk-metrics"]
 [workspace.dependencies]
 abomonation = "0.7.3"
 anyhow = "1.0.72"
-base64 = "0.13.1"
+base64 = "0.21.7"
 bellpepper = { git = "https://github.com/lurk-lab/bellpepper", branch = "dev" }
 bellpepper-core = { git = "https://github.com/lurk-lab/bellpepper", branch = "dev" }
 bincode = "1.3.3"
 clap = "4.3.17"
 ff = "0.13"
-metrics = "0.21.1"
+metrics = "0.22.0"
 neptune = { git = "https://github.com/lurk-lab/neptune", branch = "dev", features = ["abomonation"] }
 nova = { git = "https://github.com/lurk-lab/arecibo", branch = "dev", package = "arecibo" }
 once_cell = "1.18.0"
 pairing = { version = "0.23" }
 pasta_curves = { git = "https://github.com/lurk-lab/pasta_curves", branch = "dev" }
 proptest = "1.2.0"
-proptest-derive = "0.3"
+proptest-derive = "0.4"
 rand = "0.8"
 serde = "1.0"
 serde_json = { version = "1.0" }