cargo: 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](https://github.com/serde-rs/json/compare/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>

Cargo.lock

@@ -3340,9 +3340,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.67"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7f9e390c27c3c0ce8bc5d725f6e4d30a29d26659494aa4b17535f7522c5c950"
+checksum = "0f690853975602e1bfe1ccbf50504d67174e3bcf340f23b5ea9992e0587a52d8"
 dependencies = [
  "itoa",
  "ryu",