chore(deps): bump the cargo group across 1 directory with 2 updates

Bumps the cargo group with 2 updates in the / directory: protobuf and [slab](https://github.com/tokio-rs/slab).


Updates `protobuf` from 2.28.0 to 3.7.2

Updates `slab` from 0.4.10 to 0.4.11
- [Release notes](https://github.com/tokio-rs/slab/releases)
- [Changelog](https://github.com/tokio-rs/slab/blob/master/CHANGELOG.md)
- [Commits](tokio-rs/slab@v0.4.10...v0.4.11)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 3.7.2
  dependency-type: direct:production
  dependency-group: cargo
- dependency-name: slab
  dependency-version: 0.4.11
  dependency-type: indirect
  dependency-group: cargo
...

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

Author: dependabot[bot]

Cargo.lock

@@ -52,7 +52,7 @@ papaya = "0.2.1"
 pest_derive = "2.7"
 portpicker = "0.1"
 prettyplease = "0.2"
-protobuf = "2.28"
+protobuf = "3.7"
 quote = "1.0"
 rand = "0.8"
 regex = "1.4"