Bump arc-swap in /code-samples/serving/cloudevents/cloudevents-rust (#5042)

Bumps [arc-swap](https://github.com/vorner/arc-swap) from 0.4.6 to 0.4.8.
- [Release notes](https://github.com/vorner/arc-swap/releases)
- [Changelog](https://github.com/vorner/arc-swap/blob/v0.4.8/CHANGELOG.md)
- [Commits](https://github.com/vorner/arc-swap/compare/v0.4.6...v0.4.8)

---
updated-dependencies:
- dependency-name: arc-swap
  dependency-type: indirect
...

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

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

code-samples/serving/cloudevents/cloudevents-rust/Cargo.lock

@@ -322,9 +322,9 @@ dependencies = [
 
 [[package]]
 name = "arc-swap"
-version = "0.4.6"
+version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b585a98a234c46fc563103e9278c9391fde1f4e6850334da895d27edb9580f62"
+checksum = "dabe5a181f83789739c194cbe5a897dde195078fac08568d09221fd6137a7ba8"
 
 [[package]]
 name = "async-trait"