Bump serde_json from 1.0.67 to 1.0.68

Bumps [serde_json](https://github.com/serde-rs/json) from 1.0.67 to 1.0.68.
- [Release notes](https://github.com/serde-rs/json/releases)
- [Commits](serde-rs/json@v1.0.67...v1.0.68)

---
updated-dependencies:
- dependency-name: serde_json
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Cargo.lock

@@ -20,7 +20,7 @@ anyhow = "1.0.44"
 log = "0.4"
 semver = "1.0" # Keep in sync with version pulled by Cargo
 serde = { version = "1.0.130", features = ["derive"] }
-serde_json = "1.0.67"
+serde_json = "1.0.68"
 
 [dev-dependencies]
 quickcheck = "1.0"