chore: bump serde from 1.0.185 to 1.0.188

Bumps [serde](https://github.com/serde-rs/serde) from 1.0.185 to 1.0.188.
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.185...v1.0.188)

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

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -22,7 +22,7 @@ libc = "0.2.81"
 streaming-iterator = "0.1.5"
 bitflags = "1.2.1"
 humantime = {version = "2.1.0", optional = true}
-serde = {version = "1.0.118", features = ["derive"], optional = true}
+serde = {version = "1.0.188", features = ["derive"], optional = true}
 serde_json = {version = "1.0.67", optional = true}
 bincode = {version = "1.3.1", optional = true}
 tskit-derive = {version = "0.2.0", path = "tskit-derive", optional = true}
@@ -32,7 +32,7 @@ delegate = "0.10.0"
 [dev-dependencies]
 anyhow = {version = "1.0.66"}
 clap = {version = "~3.2.8", features = ["derive"]}
-serde = {version = "1.0.118", features = ["derive"]}
+serde = {version = "1.0.188", features = ["derive"]}
 serde-pickle = "1.1.0"
 serde_json = {version = "1.0.67"}
 bincode = "1.3.1"