Bump jsonschema from 0.18.0 to 0.20.0

Bumps [jsonschema](https://github.com/Stranger6667/jsonschema-rs) from 0.18.0 to 0.20.0.
- [Release notes](https://github.com/Stranger6667/jsonschema-rs/releases)
- [Changelog](https://github.com/Stranger6667/jsonschema-rs/blob/master/CHANGELOG.md)
- [Commits](Stranger6667/jsonschema-rs@rust-v0.18.0...rust-v0.20.0)

---
updated-dependencies:
- dependency-name: jsonschema
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

serde_with/Cargo.toml

@@ -140,7 +140,7 @@ time_0_3 = {package = "time", version = "~0.3.36", optional = true, default-feat
 expect-test = "1.5.0"
 fnv = "1.0.6"
 glob = "0.3.0"
-jsonschema = { version = "0.18.0", default-features = false, features = ["resolve-file"] }
+jsonschema = { version = "0.20.0", default-features = false, features = ["resolve-file"] }
 mime = "0.3.16"
 pretty_assertions = "1.4.0"
 regex = {version = "1.10.3", default-features = false, features = ["std"]}