Update worker requirement from 0.3.4 to 0.4.0

Updates the requirements on [worker](https://github.com/cloudflare/workers-rs) to permit the latest version.
- [Release notes](https://github.com/cloudflare/workers-rs/releases)
- [Commits](cloudflare/workers-rs@v0.3.4...v0.4.0)

---
updated-dependencies:
- dependency-name: worker
  dependency-type: direct:production
...

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

collectr/Cargo.toml

@@ -18,7 +18,7 @@ path = "src/worker.rs"
 
 [dependencies]
 data_model = { path = "../data_model" }
-worker = { version = "0.3.4", features = ["queue"] }
+worker = { version = "0.4.0", features = ["queue"] }
 serde_derive = "~1.0"
 serde = "~1.0"
 serde_json = "1.0.107"