Bump tracing-subscriber from 0.3.20 to 0.3.22 in /backend (#169)

Bumps [tracing-subscriber](https://github.com/tokio-rs/tracing) from 0.3.20 to 0.3.22.
- [Release notes](https://github.com/tokio-rs/tracing/releases)
- [Commits](tokio-rs/tracing@tracing-subscriber-0.3.20...tracing-subscriber-0.3.22)

---
updated-dependencies:
- dependency-name: tracing-subscriber
  dependency-version: 0.3.22
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/Cargo.lock

@@ -20,7 +20,7 @@
   toml = { version = "0.9.8" }
   tower-http = { version = "0.6", features = [ "cors" ] }
   tracing = { version = "0.1" }
-  tracing-subscriber = { version = "0.3.20", features = [ "env-filter" ] }
+  tracing-subscriber = { version = "0.3.22", features = [ "env-filter" ] }
 
   strata-bridge-primitives = { git = "https://github.com/alpenlabs/strata-bridge.git", tag = "v0.2.0-rc3" }
   strata-bridge-rpc = { git = "https://github.com/alpenlabs/strata-bridge.git", features = [